0001437749-23-028607 | 10-Q | XBRL Viewer

Issuer Rule 10b5-1, Material Terms [Text Block]

Item 5. Other Information

On July 28, 2023, Eric J. Gehringer, Executive Vice President - Operations for Union Pacific Railroad Company, adopted a trading plan intended to satisfy Rule 10b5-1(c) to sell up to 1,274 shares of Union Pacific Corporation common stock on or after October 30, 2023, subject to certain conditions.

On August 22, 2023, V. James Vena, Chief Executive Officer, adopted a trading plan intended to satisfy Rule 10b5-1(c) to purchase up to 4,500 shares of Union Pacific Corporation common stock on or after November 21, 2023, subject to certain conditions.

Note 12 - Financial Instruments (Details Textual) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss, Current	$ 16	$ 46
Debt Instrument, Fair Value Disclosure	25,900	28,100
Fair Value of Total Debt Less of Carrying Value	7,000	5,200
Fair Value, Inputs, Level 2 [Member]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss, Current	$ 16	$ 46

Condensed Consolidated Statements of Financial Position (Unaudited) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 750	$ 973
Short-term investments (Note 12)	16	46
Accounts receivable, net (Note 9)	1,934	1,891
Materials and supplies	770	741
Other current assets	343	301
Total current assets	3,813	3,952
Investments	2,580	2,375
Properties, net (Note 10)	57,010	56,038
Operating lease assets	1,670	1,672
Other assets	1,467	1,412
Total assets	66,540	65,449
Current liabilities:
Accounts payable and other current liabilities (Note 11)	3,580	3,842
Debt due within one year (Note 13)	1,724	1,678
Total current liabilities	5,304	5,520
Debt due after one year (Note 13)	31,153	31,648
Operating lease liabilities	1,244	1,300
Deferred income taxes	13,095	13,033
Other long-term liabilities	1,740	1,785
Total liabilities	52,536	53,286
Common shareholders' equity:
Common shares, $2.50 par value, 1,400,000,000 authorized; 1,112,868,076 and 1,112,623,886 issued; 609,563,088 and 612,393,321 outstanding, respectively	2,782	2,782
Paid-in-surplus	5,166	5,080
Retained earnings	61,235	58,887
Treasury stock	(54,682)	(54,004)
Accumulated other comprehensive loss (Note 8)	(497)	(582)
Total common shareholders' equity	14,004	12,163
Total liabilities and common shareholders' equity	$ 66,540	$ 65,449

Note 5 - Other Income (Details Textual) - USD ($)
$ in Millions

3 Months Ended

9 Months Ended

Sep. 30, 2023

Sep. 30, 2022

Sep. 30, 2023

Sep. 30, 2022

Profit (Loss) from Real Estate Operations

^[1]

$ 90

$ 103

$ 335

$ 309

Real Estate Transaction [Member]

Profit (Loss) from Real Estate Operations

$ 107

Land [Member] | Colorado Department of Transportation [Member]

Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property

$ 35

Land [Member] | Illinois State Toll Highway Authority [Member]

Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property

$ 79

[1]

The three months ended September 30, 2022, includes a $35 million gain from a sale to the Colorado Department of Transportation. The nine months ended September 30, 2023, includes a one-time $107 million transaction. The nine months ended September 30, 2022, also includes a $79 million gain from a land sale to the Illinois State Toll Highway Authority.

Note 2 - Operations and Segmentation (Details Textual) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)
Number of Reportable Segments			1
Number of Operating Segments				1
Revenue from Contract with Customer, Excluding Assessed Tax	$ 5,941	$ 6,566	$ 17,960	$ 18,695
MEXICO
Revenue from Contract with Customer, Excluding Assessed Tax	$ 673	$ 708	$ 2,100	$ 2,000

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 924
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479941/924-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-5

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-42

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 40
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-40

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 41
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-41

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-4

Balance (in shares) at Dec. 31, 2021

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Operating Activities
Net income	$ 1,528	$ 1,895	$ 4,727	$ 5,360
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	580	563	1,729	1,677
Deferred and other income taxes			59	180
Other operating activities, net			(121)	(93)
Changes in current assets and liabilities:
Accounts receivable, net			(38)	(330)
Materials and supplies			(29)	(173)
Other current assets			(73)	(9)
Accounts payable and other current liabilities			(381)	433
Income and other taxes			111	25
Cash provided by operating activities			5,984	7,070
Investing Activities
Capital investments			(2,582)	(2,690)
Other investing activities, net			(68)	131
Cash used in investing activities			(2,650)	(2,559)
Financing Activities
Dividends paid			(2,380)	(2,362)
Debt repaid			(2,179)	(2,185)
Debt issued (Note 13)			1,599	6,080
Share repurchase programs (Note 15)			(705)	(5,497)
Other financing activities, net			125	(246)
Cash used in financing activities			(3,540)	(4,210)
Net change in cash, cash equivalents, and restricted cash			(206)	301
Cash, cash equivalents, and restricted cash at beginning of year			987	983
Cash, cash equivalents, and restricted cash at end of period	781	1,284	781	1,284
Non-cash investing and financing activities:
Capital investments accrued but not yet paid			187	172
Common shares repurchased but not yet paid			6	80
Cash (paid for)/received from:
Income taxes, net of refunds			(1,155)	(1,473)
Interest, net of amounts capitalized			(1,113)	(980)
Cash and cash equivalents	750	1,267	750	1,267
Restricted cash equivalents in other current assets	22	13	22	13
Restricted cash equivalents in other assets	9	4	9	4
Cash, cash equivalents, and restricted cash at end of period	$ 781	$ 1,284	$ 781	$ 1,284

Condensed Consolidated Statements of Comprehensive Income (Unaudited) (Parentheticals) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Total other comprehensive income/(loss), tax	$ 1	$ 6	$ 4	$ 17

Condensed Consolidated Statements of Changes in Common Shareholders' Equity (Unaudited) - USD ($)
$ in Millions

Common Stock [Member]

Treasury Stock, Common [Member]

Additional Paid-in Capital [Member]

Retained Earnings [Member]

AOCI Attributable to Parent [Member]

^[1]

Total

1,112,400,000

(473,600,000)

Balance at Dec. 31, 2021

$ 2,781

$ (47,734)

$ 4,979

$ 55,049

$ (914)

$ 14,161

5,360

Conversion, stock option exercises, forfeitures, ESPP, and other [b]

^[2]

^[3]

$ 1

$ (10)

$ 79

(23,600,000)

(23,605,223)

$ 0

$ (5,565)

(12)

$ (5,577)

Conversion, stock option exercises, forfeitures, ESPP, and other [b] (in shares)

$ 0

(2,362)

200,000

400,000

^[3]

Balance (in shares) at Sep. 30, 2022

1,112,600,000

(496,800,000)

Balance at Sep. 30, 2022

$ 2,782

$ (53,309)

5,055

58,047

(832)

11,743

Balance (in shares) at Jun. 30, 2022

1,112,600,000

(487,500,000)

Balance at Jun. 30, 2022

$ 2,781

$ (51,218)

5,030

56,958

(841)

12,710

1,895

Conversion, stock option exercises, forfeitures, ESPP, and other [b]

^[4]

^[3]

$ 1

$ 11

$ 37

(9,500,000)

(9,490,339)

$ 0

$ (2,102)

Balance (in shares) at Sep. 30, 2022

$ 0

(806)

1,112,600,000

(496,800,000)

Balance at Sep. 30, 2022

$ 2,782

$ (53,309)

5,055

58,047

(832)

11,743

Balance (in shares) at Dec. 31, 2022

1,112,600,000

(500,200,000)

Balance at Dec. 31, 2022

$ 2,782

$ (54,004)

5,080

58,887

(582)

12,163

4,727

Conversion, stock option exercises, forfeitures, ESPP, and other [b]

^[2]

^[3]

$ 0

$ 34

$ 120

(3,500,000)

(3,515,284)

$ 0

$ (712)

Conversion, stock option exercises, forfeitures, ESPP, and other [b] (in shares)

$ 0

(2,379)

300,000

400,000

^[3]

Balance (in shares) at Sep. 30, 2023

1,112,900,000

(503,300,000)

Balance at Sep. 30, 2023

$ 2,782

$ (54,682)

5,166

61,235

(497)

14,004

Balance (in shares) at Jun. 30, 2023

1,112,900,000

(503,500,000)

Balance at Jun. 30, 2023

$ 2,782

$ (54,699)

5,128

60,500

(517)

13,194

1,528

Conversion, stock option exercises, forfeitures, ESPP, and other [b]

^[4]

^[3]

$ 0

$ 17

$ 55

$ 0

Conversion, stock option exercises, forfeitures, ESPP, and other [b] (in shares)

$ 0

(793)

200,000

^[3]

Balance (in shares) at Sep. 30, 2023

1,112,900,000

(503,300,000)

Balance at Sep. 30, 2023

$ 2,782

$ (54,682)

$ 5,166

$ 61,235

$ (497)

$ 14,004

[1]	AOCI = Accumulated Other Comprehensive Income/Loss (Note 8)
[2]	Net of deferred taxes of ($4) million and ($17) million during the nine months ended September 30, 2023 and 2022, respectively.
[3]	ESPP = employee stock purchase plan (Note 3)
[4]	Net of deferred taxes of ($1) million and ($6) million during the three months ended September 30, 2023 and 2022, respectively.

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 323
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481687/323-10-50-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 28
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-28

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482765/220-10-50-6

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-8

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-9

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-4

Reference 13: http://www.xbrl.org/2003/role/exampleRef
-Topic 946
-SubTopic 830
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480167/946-830-55-10

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section 45
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483581/946-220-45-7

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(18))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(9))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-09(1)(d))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-3

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(i))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 20: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(ii))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iii)(A))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iv))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(5))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(i))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(A))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(B))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iv))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(5))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 29: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 30: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 31: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-60B

Reference 32: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-31

Reference 33: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 34: http://www.xbrl.org/2003/role/disclosureRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483499/205-20-50-7

Reference 35: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-28

Reference 36: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-1A

Reference 37: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-1B

Reference 38: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(20))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 39: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(22))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

Amount of equity (deficit) attributable to parent. Excludes temporary equity and equity attributable to noncontrolling interest.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 852
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481372/852-10-55-10

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 946
-SubTopic 830
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480167/946-830-55-12

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-04(19))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479617/946-210-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.6-05(4))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479617/946-210-S99-2

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-09(4)(b))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-3

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-09(6))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-3

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-09(7))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-3

Reference 8: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 9: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 323
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481687/323-10-50-3

Reference 10: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 28
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-28

Reference 11: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 12: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(31))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 13: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(30))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 14: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 4.E)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480418/310-10-S99-2

Other Information - Rule 10b5-1 Disclosure (Details Textual) - shares			1 Months Ended	2 Months Ended
	Aug. 22, 2023	Jul. 28, 2023	Sep. 30, 2023	Sep. 30, 2023
Executive Vice President of Operations [Member]
Issuer Rule 10b5-1, Individual Name				Eric J. Gehringer
Issuer Rule 10b5-1, Individual Title				Executive Vice President - Operations
Issuer Rule 10b5-1, Aggregate Available Shares (in shares)		1,274
Issuer Rule 10b5-1, Arrangement Termination Date		Oct. 30, 2023
Chief Executive Officer [Member]
Issuer Rule 10b5-1, Individual Name			V. James Vena
Issuer Rule 10b5-1, Individual Title			Chief Executive Officer
Issuer Rule 10b5-1, Aggregate Available Shares (in shares)	4,500
Issuer Rule 10b5-1, Arrangement Termination Date	Nov. 21, 2023

Note 14 - Commitments and Contingencies - Personal Injury Liability Activity (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Balance, Current	$ 293		$ 242
Personal Injury [Member]
Balance	361	$ 325
Current year accruals	81	79
Changes in estimates for prior years	55	36
Payments	(104)	(93)
Balance	393	347
Balance, Current	$ 105	$ 77

Note 9 - Accounts Receivable

9 Months Ended

Sep. 30, 2023

Loans, Notes, Trade and Other Receivables Disclosure [Text Block]

9. Accounts Receivable

Accounts receivable includes freight and other receivables reduced by an allowance for doubtful accounts. At September 30, 2023, and December 31, 2022, our accounts receivables were reduced by $9 million and $10 million, respectively. Receivables not expected to be collected in one year and the associated allowances are classified as other assets in our Condensed Consolidated Statements of Financial Position. At September 30, 2023, and December 31, 2022, receivables classified as other assets were reduced by allowances of $71 million and $58 million, respectively.

Receivables Securitization Facility – The Railroad maintains an $800 million, 3-year receivables securitization facility (the Receivables Facility) maturing in July 2025. Under the Receivables Facility, the Railroad sells most of its eligible third-party receivables to Union Pacific Receivables, Inc. (UPRI), a consolidated, wholly-owned, bankruptcy-remote subsidiary that may subsequently transfer, without recourse, an undivided interest in accounts receivable to investors. The investors have no recourse to the Railroad’s other assets except for customary warranty and indemnity claims. Creditors of the Railroad do not have recourse to the assets of UPRI.

The amount recorded under the Receivables Facility was $0 and $100 million at September 30, 2023, and December 31, 2022, respectively. The Receivables Facility was supported by $1.6 billion of accounts receivable as collateral at both September 30, 2023, and December 31, 2022, which, as a retained interest, is included in accounts receivable, net in our Condensed Consolidated Statements of Financial Position.

The outstanding amount the Railroad maintains under the Receivables Facility may fluctuate based on current cash needs. The maximum allowed under the Receivables Facility is $800 million with availability directly impacted by eligible receivables, business volumes, and credit risks, including receivables payment quality measures such as default and dilution ratios. If default or dilution ratios increase one percent, the allowable outstanding amount under the Receivables Facility would not materially change.

The costs of the Receivables Facility include interest, which will vary based on prevailing benchmark and commercial paper rates, program fees paid to participating banks, commercial paper issuance costs, and fees of participating banks for unused commitment availability. The costs of the Receivables Facility are included in interest expense and were $4 million for both the three months ended September 30, 2023 and 2022 , and $8 million for both the nine months ended September 30, 2023 and 2022 .

Note 4 - Retirement Plans - Components of Net Periodic Pension and OPEB Cost (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Net periodic pension (benefit)/cost	$ 1	$ (1)	$ (2)	$ 10
Pension Plan [Member]
Service cost	13	21	38	73
Interest cost	48	31	140	93
Expected return on plan assets	(62)	(74)	(186)	(220)
Amortization of actuarial loss	$ 2	$ 21	$ 6	$ 64

Note 5 - Other Income

9 Months Ended

Sep. 30, 2023

Other Income and Other Expense Disclosure [Text Block]

5. Other Income

Other income included the following:

	Three Months Ended						Nine Months Ended
	September 30,						September 30,
Millions	*2023*			2022			*2023*			2022
Real estate income [a]	$	90		$	103		$	335		$	309
Net periodic pension benefit/(costs)		12			22			40			63
Environmental remediation and restoration		(9	)		(4	)		(31	)		(35	)
Other		13			3			39			(3	)
Total	$	106		$	124		$	383		$	334

[a]

The three months ended September 30, 2022, includes a $35 million gain from a sale to the Colorado Department of Transportation. The nine months ended September 30, 2023, includes a one-time $107 million transaction. The nine months ended September 30, 2022, also includes a $79 million gain from a land sale to the Illinois State Toll Highway Authority.

Note 8 - Accumulated Other Comprehensive Income/Loss (Tables)

9 Months Ended

Sep. 30, 2023

Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]

Millions	Defined benefit plans				Foreign currency translation				Unrealized gain on derivative instruments [a]			Total
Balance at July 1, 2023		$	(373	)		$	(160	)		$	16	$	(517	)
Other comprehensive income/(loss) before reclassifications			(1	)			22				-		21
Amounts reclassified from accumulated other comprehensive income/(loss) [b]			(1	)			-				-		(1	)
Net quarter-to-date other comprehensive income/(loss), net of taxes of ($1) million			(2	)			22				-		20
Balance at September 30, 2023		$	(375	)		$	(138	)		$	16	$	(497	)

Balance at July 1, 2022		$	(629	)		$	(212	)		$	-	$	(841	)
Other comprehensive income/(loss) before reclassifications			-				(6	)			-		(6	)
Amounts reclassified from accumulated other comprehensive income/(loss) [b]			15				-				-		15
Net quarter-to-date other comprehensive income/(loss), net of taxes of ($6) million			15				(6	)			-		9
Balance at September 30, 2022		$	(614	)		$	(218	)		$	-	$	(832	)

Millions	Defined benefit plans				Foreign currency translation				Unrealized gain on derivative instruments [a]			Total
Balance at January 1, 2023		$	(378	)		$	(204	)		$	-	$	(582	)
Other comprehensive income/(loss) before reclassifications			5				66				16		87
Amounts reclassified from accumulated other comprehensive income/(loss) [b]			(2	)			-				-		(2	)
Net year-to-date other comprehensive income/(loss), net of taxes of ($4) million			3				66				16		85
Balance at September 30, 2023		$	(375	)		$	(138	)		$	16	$	(497	)

Balance at January 1, 2022		$	(658	)		$	(256	)		$	-	$	(914	)
Other comprehensive income/(loss) before reclassifications			-				38				-		38
Amounts reclassified from accumulated other comprehensive income/(loss) [b]			44				-				-		44
Net year-to-date other comprehensive income/(loss), net of taxes of ($17) million			44				38				-		82
Balance at September 30, 2022		$	(614	)		$	(218	)		$	-	$	(832	)

Note 3 - Stock-based Compensation - Changes in Retention Awards (Details) - Retention Awards [Member] shares in Thousands	9 Months Ended
	Sep. 30, 2023 $ / shares shares
Nonvested, beginning balance (in shares) \| shares	1,069
Nonvested, weighted-average grant-date fair value, beginning balance (in dollars per share) \| $ / shares	$ 196.47
Granted (in shares) \| shares	296
Granted, weighted-average grant-date fair value (in dollars per share) \| $ / shares	$ 202.83
Vested (in shares) \| shares	(305)
Vested, weighted-average grant-date fair value (in dollars per share) \| $ / shares	$ 163.27
Forfeited (in shares) \| shares	(39)
Forfeited, weighted-average grant-date fair value (in dollars per share) \| $ / shares	$ 205.35
Nonvested, ending balance (in shares) \| shares	1,021
Nonvested, weighted-average grant-date fair value, ending balance (in dollars per share) \| $ / shares	$ 207.89

Document And Entity Information - shares	9 Months Ended
Document And Entity Information - shares	Sep. 30, 2023	Oct. 13, 2023
Document Information [Line Items]
Entity Central Index Key	0000100885
Entity Registrant Name	UNION PACIFIC CORP
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2023
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2023
Document Transition Report	false
Entity File Number	1-6075
Entity Incorporation, State or Country Code	UT
Entity Tax Identification Number	13-2626465
Entity Address, Postal Zip Code	68179
Entity Address, Address Line One	1400 Douglas Street
Entity Address, City or Town	Omaha
Entity Address, State or Province	NE
City Area Code	402
Local Phone Number	544-5000
Title of 12(b) Security	Common Stock (Par Value $2.50 per share)
Trading Symbol	UNP
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		609,597,495

Note 7 - Earnings Per Share - Schedule of Reconciliation (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Net income	$ 1,528	$ 1,895	$ 4,727	$ 5,360
Weighted-average number of shares outstanding:
Basic (in shares)	608.7	620.4	609.3	626.1
Diluted (in shares)	609.8	621.5	610.3	627.4
Earnings per share – basic (in dollars per share)	$ 2.51	$ 3.05	$ 7.76	$ 8.56
Earnings per share – diluted (in dollars per share)	$ 2.51	$ 3.05	$ 7.75	$ 8.54
Stock options excluded as their inclusion would be anti-dilutive (in shares)	1.0	0.3	0.9	0.3
Share-Based Payment Arrangement, Option [Member]
Weighted-average number of shares outstanding:
Dilutive effect of share based payment awards (in shares)	0.4	0.5	0.4	0.7
Retention Awards [Member]
Weighted-average number of shares outstanding:
Dilutive effect of share based payment awards (in shares)	0.7	0.6	0.6	0.6

Note 5 - Other Income - Schedule of Other Income (Details) - USD ($)
$ in Millions

3 Months Ended

9 Months Ended

Sep. 30, 2023

Sep. 30, 2022

Sep. 30, 2023

Sep. 30, 2022

Real estate income [a]

^[1]

$ 90

$ 103

$ 335

$ 309

Net periodic pension benefit/(costs)

Environmental remediation and restoration

(9)

(4)

(31)

(35)

Other

(3)

Total

$ 106

$ 124

$ 383

$ 334

[1]

Note 11 - Accounts Payable and Other Current Liabilities (Tables)

9 Months Ended

Sep. 30, 2023

Schedule of Accounts Payable and Accrued Liabilities [Table Text Block]

	*Sep. 30,*			Dec. 31,
Millions		*2023*			2022
Accounts payable		$	936		$	784
Income and other taxes payable			701			628
Compensation-related accruals			547			938
Current operating lease liabilities			362			331
Accrued casualty costs			293			242
Interest payable			248			379
Equipment rents payable			99			109
Other			394			431
Total accounts payable and other current liabilities		$	3,580		$	3,842

Note 3 - Stock-based Compensation- Stock Option Assumption (Details) - Share-Based Payment Arrangement, Option [Member] - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Risk-free interest rate	3.90%	1.60%
Dividend yield	2.60%	1.90%
Expected life (years) (Year)	4 years 6 months	4 years 4 months 24 days
Volatility	29.30%	28.70%
Weighted-average grant-date fair value of options granted (in dollars per share)	$ 48.31	$ 51.92

Note 3 - Stock-based Compensation (Details Textual) shares in Thousands, $ in Millions	9 Months Ended
	Sep. 30, 2023 USD ($) shares
Share-Based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)	10 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)	3 years
Share-based Compensation Arrangement by Share-based Payment Award, Conditions (in shares) \| shares	0
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 20
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)	1 year 3 months 18 days
Retention Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)	4 years
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 98
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)	1 year 7 months 6 days
Performance Retention Awards [Member]
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 16
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)	1 year 1 month 6 days
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period (Month)	37 months
Share-based Compensation Arrangement by Share-based Payment Award, Performance Period (Year)	3 years

Note 15 - Share Repurchase Programs

9 Months Ended

Sep. 30, 2023

Treasury Stock [Text Block]

15. Share Repurchase Programs

Effective April 1, 2022, our Board of Directors authorized the repurchase of up to 100 million shares of our common stock by March 31, 2025. As of September 30, 2023, we repurchased a total of 19.6 million shares of our common stock under the 2022 authorization. These repurchases may be made on the open market or through other transactions. Our management has sole discretion with respect to determining the timing and amount of these transactions.

Our previous authorization, which was effective April 1, 2019, through March 31, 2022, was approved by our Board of Directors for up to 150 million shares of common stock. As of March 31, 2022, we repurchased a total of 83.3 million shares of our common stock under the 2019 authorization.

The table below represents shares repurchased under repurchase programs in the nine months ended September 30, 2023 and 2022:

	Number of Shares Purchased					Average Price Paid [a]
		*2023*		2022		*2023*		2022
First quarter [b]			2,908,703		11,014,201	$	203.19	$	249.95
Second quarter [c]			606,581		3,100,683		199.81		232.87
Third quarter			-		9,490,339		-		221.52
Total			3,515,284		23,605,223	$	202.61	$	236.28
Remaining number of shares that may be repurchased under current authority									80,392,027

[a]	In the period of the final settlement, the average price paid under the accelerated share repurchase programs is calculated based on the total program value less the value assigned to the initial delivery of shares. The average price of the completed 2022 accelerated share repurchase programs was $248.32.
[b]	Includes 7,012,232 shares repurchased in 2022* under accelerated share repurchase programs.*
[c]	Includes an incremental 1,847,185 shares received upon final settlement in 2022* under accelerated share repurchase programs.*

Management's assessments of market conditions and other pertinent factors guide the timing, manner, and volume of all repurchases. We expect to fund any share repurchases under this program through cash generated from operations, the sale or lease of various operating and non-operating properties, debt issuances, and cash on hand. Open market repurchases are recorded in treasury stock at cost, which includes any applicable commissions, fees, and excise taxes.

Accelerated Share Repurchase Programs – The Company has established accelerated share repurchase programs (ASRs) with financial institutions to repurchase shares of our common stock. These ASRs have been structured so that at the time of commencement, we pay a specified amount to the financial institutions and receive an initial delivery of shares. Additional shares may be received at the time of settlement. The final number of shares to be received is based on the volume weighted average price of the Company’s common stock during the ASR term, less a discount and subject to potential adjustments pursuant to the terms of such ASR.

On February 18, 2022, the Company received 7,012,232 shares of its common stock repurchased under ASRs for an aggregate of $2.2 billion. Upon settlement of these ASRs in the second quarter of 2022, we received 1,847,185 additional shares.

ASRs are accounted for as equity transactions, and at the time of receipt, shares are included in treasury stock at fair market value as of the corresponding initiation or settlement date. The Company reflects shares received as a repurchase of common stock in the weighted average common shares outstanding calculation for basic and diluted earnings per share.

Note 2 - Operations and Segmentation (Tables)

9 Months Ended

Sep. 30, 2023

Disaggregation of Revenue [Table Text Block]

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
Millions	*2023*		2022		*2023*		2022
Bulk	$	1,766	$	1,959	$	5,420	$	5,604
Industrial		2,057		2,194		6,160		6,206
Premium		1,722		1,956		5,190		5,581
Total freight revenues	$	5,545	$	6,109	$	16,770	$	17,391
Other subsidiary revenues		226		231		681		669
Accessorial revenues		142		212		442		596
Other		28		14		67		39
Total operating revenues	$	5,941	$	6,566	$	17,960	$	18,695

Note 15 - Share Repurchase Programs (Details Textual) - USD ($)
$ / shares in Units, $ in Millions

3 Months Ended

9 Months Ended

18 Months Ended

36 Months Ended

Feb. 18, 2022

Sep. 30, 2023

Jun. 30, 2023

Mar. 31, 2023

Sep. 30, 2022

Jun. 30, 2022

Mar. 31, 2022

Sep. 30, 2023

Sep. 30, 2022

Sep. 30, 2023

Mar. 31, 2022

Apr. 01, 2022

Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)

150,000,000

100,000,000

Treasury Stock, Shares, Acquired (in shares)

606,581

2,908,703

9,490,339

3,100,683

^[1]

11,014,201

^[2]

3,515,284

23,605,223

19,600,000

83,300,000

Treasury Stock Acquired, Average Cost Per Share (in dollars per share)

$ 0

$ 199.81

$ 203.19

$ 221.52

$ 232.87

^[1],[3]

$ 249.95

^[2],[3]

$ 202.61

$ 236.28

Treasury Stock, Value, Acquired, Cost Method, Including Amount Paid in Excess

$ (0)

$ 2,102

$ 712

$ 5,577

Accelerated Share Repurchase Programs (ASRs) [Member]

Treasury Stock, Shares, Acquired (in shares)

7,012,232

1,847,185

7,012,232

Treasury Stock Acquired, Average Cost Per Share (in dollars per share)

$ 248.32

Treasury Stock, Value, Acquired, Cost Method, Including Amount Paid in Excess

$ 2,200

[1]	Includes 1,847,185 shares repurchased in 2022 under accelerated share repurchase programs.
[2]	Includes 7,012,232 shares repurchased in 2022 under accelerated share repurchase programs.
[3]	In the period of the final settlement, the average price paid under the accelerated share repurchase programs is calculated based on the total program value less the value assigned to the initial delivery of shares. The average price of the completed 2022 accelerated share repurchase programs was $248.32.

Note 1 - Basis of Presentation

9 Months Ended

Sep. 30, 2023

Basis of Accounting [Text Block]

1. Basis of Presentation

Our Condensed Consolidated Financial Statements are unaudited and reflect all adjustments (consisting of normal and recurring adjustments) that are, in the opinion of management, necessary for their fair presentation in conformity with accounting principles generally accepted in the United States of America (GAAP). Pursuant to the rules and regulations of the Securities and Exchange Commission (SEC), certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted. Accordingly, this Quarterly Report on Form 10-Q should be read in conjunction with our Consolidated Financial Statements and notes thereto contained in our 2022 Annual Report on Form 10-K. Our Consolidated Statement of Financial Position at December 31, 2022, is derived from audited financial statements. The results of operations for the nine months ended September 30, 2023, are not necessarily indicative of the results for the entire year ending December 31, 2023.

The Condensed Consolidated Financial Statements are presented in accordance with GAAP as codified in the Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC). Certain prior period amounts have been reclassified to conform to the current period financial statement presentation.

Note 8 - Accumulated Other Comprehensive Income/Loss - Schedule of Reclassification (Details) - USD ($)
$ in Millions

3 Months Ended

9 Months Ended

Sep. 30, 2023

Sep. 30, 2022

Sep. 30, 2023

Sep. 30, 2022

$ 13,194

$ 12,710

$ 12,163

$ 14,161

^[1]

^[2]

Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]

14,004

11,743

14,004

11,743

Other comprehensive income/(loss) before reclassifications

(373)

(629)

(378)

(658)

(1)

Amounts reclassified from accumulated other comprehensive income/(loss) [b]

^[3]

(1)

(2)

(2)

Accumulated Foreign Currency Adjustment Attributable to Parent [Member]

(375)

(614)

(375)

(614)

Other comprehensive income/(loss) before reclassifications

(160)

(212)

(204)

(256)

(6)

Amounts reclassified from accumulated other comprehensive income/(loss) [b]

^[3]

(6)

Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]

(138)

(218)

(138)

(218)

Other comprehensive income/(loss) before reclassifications

^[4]

^[4]

Amounts reclassified from accumulated other comprehensive income/(loss) [b]

^[3]

^[4]

^[4]

AOCI Attributable to Parent [Member]

^[4]

Other comprehensive income/(loss) before reclassifications

^[5]

(517)

(841)

(582)

(914)

(6)

Amounts reclassified from accumulated other comprehensive income/(loss) [b]

^[3]

(1)

(2)

^[5]

^[5]

$ (497)

$ (832)

$ (497)

$ (832)

[1]	Net of deferred taxes of ($1) million and ($6) million during the three months ended September 30, 2023 and 2022, respectively.
[2]	Net of deferred taxes of ($4) million and ($17) million during the nine months ended September 30, 2023 and 2022, respectively.
[3]	The accumulated other comprehensive income/loss reclassification components are 1) prior service cost/credit and 2) net actuarial loss, which are both included in the computation of net periodic pension benefit/cost. See Note 4 Retirement Plans for additional details.
[4]	Related to interest rate swaps from equity method investments.
[5]	AOCI = Accumulated Other Comprehensive Income/Loss (Note 8)

Amount of equity (deficit) attributable to parent. Excludes temporary equity and equity attributable to noncontrolling interest.

Note 13 - Debt (Tables)

9 Months Ended

Sep. 30, 2023

Unsecured Fixed Rate Debt Securities Issued Under Current Shelf Registration [Table Text Block]

Date	Description of Securities
February 21, 2023	$0.50 billion of 4.750% Notes due February 21, 2026
	$0.50 billion of 4.950% Notes due May 15, 2053

Note 3 - Stock-based Compensation - Stock-based Compensation (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Stock options	$ 4	$ 4	$ 12	$ 11
Retention awards	24	13	57	54
Total stock-based compensation, before tax	32	21	84	77
Excess income tax benefits from equity compensation plans	2	2	9	20
Employee Stock [Member]
ESPP	$ 4	$ 4	$ 15	$ 12

Note 10 - Properties (Tables)

9 Months Ended

Sep. 30, 2023

Property, Plant and Equipment [Table Text Block]

Millions, Except Estimated Useful Life			Accumulated		Net Book		Estimated
As of September 30, 2023	Cost		Depreciation		Value		Useful Life
Land	$	5,372	$	N/A	$	5,372		N/A
Road:
Rail and other track material		18,747		7,280		11,467		42
Ties		11,934		3,844		8,090		34
Ballast		6,320		2,031		4,289		34
Other roadway [a]		22,899		5,269		17,630		47
Total road		59,900		18,424		41,476		N/A
Equipment:
Locomotives		9,317		3,667		5,650		18
Freight cars		2,710		945		1,765		23
Work equipment and other		1,319		527		792		17
Total equipment		13,346		5,139		8,207		N/A
Technology and other		1,294		559		735		12
Construction in progress		1,220		-		1,220		N/A
Total	$	81,132	$	24,122	$	57,010		N/A

Millions, Except Estimated Useful Life			Accumulated		Net Book		Estimated
As of December 31, 2022	Cost		Depreciation		Value		Useful Life
Land	$	5,344	$	N/A	$	5,344		N/A
Road:
Rail and other track material		18,419		7,096		11,323		43
Ties		11,676		3,699		7,977		34
Ballast		6,222		1,950		4,272		34
Other roadway [a]		22,411		4,970		17,441		47
Total road		58,728		17,715		41,013		N/A
Equipment:
Locomotives		9,166		3,606		5,560		18
Freight cars		2,562		898		1,664		23
Work equipment and other		1,253		473		780		17
Total equipment		12,981		4,977		8,004		N/A
Technology and other		1,254		525		729		12
Construction in progress		948		-		948		N/A
Total	$	79,255	$	23,217	$	56,038		N/A

Note 8 - Accumulated Other Comprehensive Income/Loss - Schedule of Reclassification (Details) (Parentheticals) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Total other comprehensive income/(loss), tax	$ 1	$ 6	$ 4	$ 17

Note 3 - Stock-based Compensation (Tables)

9 Months Ended

Sep. 30, 2023

Share-Based Payment Arrangement, Cost by Plan [Table Text Block]

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
Millions	*2023*		2022		*2023*		2022
Stock-based compensation, before tax:
Stock options	$	4	$	4	$	12	$	11
Retention awards		24		13		57		54
ESPP		4		4		15		12
Total stock-based compensation, before tax	$	32	$	21	$	84	$	77
Excess income tax benefits from equity compensation plans	$	2	$	2	$	9	$	20

Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

Weighted-Average Assumptions	*2023*			2022
Risk-free interest rate		3.9	%		1.6	%
Dividend yield		2.6	%		1.9	%
Expected life (years)		4.5			4.4
Volatility		29.3	%		28.7	%
Weighted-average grant-date fair value of options granted	$	48.31		$	51.92

Share-Based Payment Arrangement, Option, Activity [Table Text Block]

	Options (thous.)		Weighted-Average Exercise Price			Weighted-Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (millions)
Outstanding at January 1, 2023		1,974		$	169.64		6.0		$	86
Granted		351			202.81		N/A			N/A
Exercised		(165	)		113.97		N/A			N/A
Forfeited or expired		(12	)		219.18		N/A			N/A
Outstanding at September 30, 2023		2,148		$	179.06		6.1		$	66
Vested or expected to vest at September 30, 2023		2,128		$	178.73		6.1		$	66
Options exercisable at September 30, 2023		1,492		$	162.93		5.0		$	65

Cash Proceeds Received and Tax Benefit from Share-Based Payment Awards [Table Text Block]

	Three Months Ended						Nine Months Ended
	September 30,						September 30,
Millions	*2023*			2022			*2023*			2022
Intrinsic value of stock options exercised	$	10		$	7		$	17		$	51
Cash received from option exercises		9			7			17			24
Treasury shares repurchased for employee payroll taxes		(1	)		(2	)		(3	)		(7	)
Income tax benefit realized from option exercises		2			1			4			7
Aggregate grant-date fair value of stock options vested		-			-			14			13

Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block]

	Shares (thous.)		Weighted-Average Grant-Date Fair Value
Nonvested at January 1, 2023		1,069		$	196.47
Granted		296			202.83
Vested		(305	)		163.27
Forfeited		(39	)		205.35
Nonvested at September 30, 2023		1,021		$	207.89

Schedule of Nonvested Performance-Based Units Activity [Table Text Block]

	Shares (thous.)		Weighted-Average Grant-Date Fair Value
Nonvested at January 1, 2023		594		$	199.82
Granted		251			202.81
Vested		(78	)		189.24
Unearned		(127	)		186.11
Forfeited		(13	)		220.23
Nonvested at September 30, 2023		627		$	204.69

Note 12 - Financial Instruments

9 Months Ended

Sep. 30, 2023

Financial Instruments Disclosure [Text Block]

12. Financial Instruments

Short-Term Investments – All of the Company's short-term investments consist of time deposits and government agency securities. These investments are considered Level 2 investments and are valued at amortized cost, which approximates fair value. As of September 30, 2023, and December 31, 2022, the Company had $16 million and $46 million of short-term investments, respectively. All short-term investments have a maturity of less than one year and are classified as held-to-maturity.

Fair Value of Financial Instruments – The fair value of our short- and long-term debt was estimated using a market value price model, which utilizes applicable U.S. Treasury rates along with current market quotes on comparable debt securities. All of the inputs used to determine the fair market value of the Corporation’s long-term debt are Level 2 inputs and obtained from an independent source. At September 30, 2023, the fair value of total debt was $25.9 billion, approximately $7.0 billion less than the carrying value. At December 31, 2022, the fair value of total debt was $28.1 billion, approximately $5.2 billion less than the carrying value. The fair value of the Corporation’s debt is a measure of its current value under present market conditions. The fair value of our cash equivalents approximates their carrying value due to the short-term maturities of these instruments.

Note 13 - Debt

9 Months Ended

Sep. 30, 2023

Debt Disclosure [Text Block]

13. Debt

Credit Facilities – At September 30, 2023, we had $2.0 billion of credit available under our revolving credit facility (the Facility), which is designated for general corporate purposes and supports the issuance of commercial paper. Credit facility withdrawals totaled $0 during the nine months ended September 30, 2023. Commitment fees and interest rates payable under the Facility are similar to fees and rates available to comparably rated, investment-grade borrowers. The Facility allows for borrowings at floating rates based on Term Secured Overnight Financing Rate (SOFR), plus a spread, depending upon credit ratings for our senior unsecured debt. The Facility, set to expire May 20, 2027, requires UPC to maintain a debt-to-EBITDA (earnings before interest, taxes, depreciation, and amortization) coverage ratio.

The definition of debt used for purposes of calculating the debt-to-EBITDA coverage ratio includes, among other things, certain credit arrangements, finance leases, guarantees, unfunded and vested pension benefits under Title IV of ERISA, and unamortized debt discount and deferred debt issuance costs. At September 30, 2023 , the Company was in compliance with the debt-to-EBITDA coverage ratio, which allows us to carry up to $44.3 billion of debt (as defined in the Facility), and we had $34.6 billion of debt (as defined in the Facility) outstanding at that date. The Facility does not include any other financial restrictions, credit rating triggers (other than rating-dependent pricing), or any other provision that could require us to post collateral. The Facility also includes a $150 million cross-default provision and a change-of-control provision.

During the nine months ended September 30, 2023, we issued $1.4 billion and repaid $1.3 billion of commercial paper with maturities ranging from 11 to 88 days, and at September 30, 2023, we had $302 million of commercial paper with a weighted average interest rate of 5.4% outstanding. Our revolving credit facility supports our outstanding commercial paper balances, and, unless we change the terms of our commercial paper program, our aggregate issuance of commercial paper will not exceed the amount of borrowings available under the Facility.

Shelf Registration Statement and Significant New Borrowings – On February 3, 2022, the Board of Directors renewed its authorization for the Company to issue up to $12.0 billion of debt securities under the Company’s current three-year shelf registration filed on February 10, 2021. Under our shelf registration, we may issue, from time to time any combination of debt securities, preferred stock, common stock, or warrants for debt securities or preferred stock in one or more offerings.

During the nine months ended September 30, 2023, we issued the following unsecured, fixed-rate debt securities under our shelf registration:

Date	Description of Securities
February 21, 2023	$0.50 billion of 4.750% Notes due February 21, 2026
	$0.50 billion of 4.950% Notes due May 15, 2053

We used the net proceeds from the offerings for general corporate purposes, including the repurchase of common stock pursuant to our share repurchase programs. These debt securities include change-of-control provisions. At September 30, 2023, we had remaining authority to issue up to $5.6 billion of debt securities under our shelf registration.

Receivables Securitization Facility – As of September 30, 2023, and December 31, 2022, we recorded $0 and $100 million, respectively, of borrowings under our Receivables Facility as secured debt. (See further discussion of our receivables securitization facility in Note 9).

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(c))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 470
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//470/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1E
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1E

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

Note 10 - Properties - Schedule of Property and Equipment Major Categories (Details) - USD ($)
$ in Millions

Sep. 30, 2023

Dec. 31, 2022

$ 81,132

$ 79,255

Property, Plant and Equipment, Accumulated Depreciation

57,010

56,038

24,122

23,217

Land [Member]

5,372

5,344

Roadrail and Other Track Material [Member]

5,372

5,344

18,747

18,419

Property, Plant and Equipment, Accumulated Depreciation

11,467

11,323

$ 7,280

$ 7,096

42 years

43 years

Road Ties [Member]

$ 11,934

$ 11,676

Property, Plant and Equipment, Accumulated Depreciation

8,090

7,977

$ 3,844

$ 3,699

34 years

Road Ballast [Member]

$ 6,320

$ 6,222

Property, Plant and Equipment, Accumulated Depreciation

4,289

4,272

$ 2,031

$ 1,950

34 years

Road, Other [Member]

^[1]

$ 22,899

$ 22,411

Property, Plant and Equipment, Accumulated Depreciation

17,630

^[1]

17,441

$ 5,269

^[1]

$ 4,970

47 years

^[1]

47 years

Road [Member]

$ 59,900

$ 58,728

Property, Plant and Equipment, Accumulated Depreciation

41,476

41,013

18,424

17,715

Equipment, Locomotives [Member]

9,317

9,166

Property, Plant and Equipment, Accumulated Depreciation

5,650

5,560

$ 3,667

$ 3,606

Equipment, Freight Cars [Member]

18 years

$ 2,710

$ 2,562

Property, Plant and Equipment, Accumulated Depreciation

1,765

1,664

$ 945

$ 898

Equipment, Work Equipment and Other [Member]

23 years

$ 1,319

$ 1,253

Property, Plant and Equipment, Accumulated Depreciation

792

780

$ 527

$ 473

17 years

Equipment [Member]

$ 13,346

$ 12,981

Property, Plant and Equipment, Accumulated Depreciation

8,207

8,004

5,139

4,977

Technology Equipment [Member]

1,294

1,254

Property, Plant and Equipment, Accumulated Depreciation

735

729

$ 559

$ 525

Construction in Progress [Member]

12 years

$ 1,220

$ 948

Property, Plant and Equipment, Accumulated Depreciation

1,220

948

$ 0

[1]	Other roadway includes grading, bridges and tunnels, signals, buildings, and other road assets.

Note 2 - Operations and Segmentation

9 Months Ended

Sep. 30, 2023

Nature of Operations [Text Block]

2. Operations and Segmentation

The Railroad, along with its subsidiaries and rail affiliates, is our one reportable operating segment. Although we provide and analyze revenues by commodity group, we treat the financial results of the Railroad as one segment due to the integrated nature of our rail network. Our operating revenues are primarily derived from contracts with customers for the transportation of freight from origin to destination.

The following table represents a disaggregation of our freight and other revenues:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
Millions	*2023*		2022		*2023*		2022
Bulk	$	1,766	$	1,959	$	5,420	$	5,604
Industrial		2,057		2,194		6,160		6,206
Premium		1,722		1,956		5,190		5,581
Total freight revenues	$	5,545	$	6,109	$	16,770	$	17,391
Other subsidiary revenues		226		231		681		669
Accessorial revenues		142		212		442		596
Other		28		14		67		39
Total operating revenues	$	5,941	$	6,566	$	17,960	$	18,695

Although our revenues are principally derived from customers domiciled in the U.S., the ultimate points of origination or destination for some products we transport are outside the U.S. Each of our commodity groups includes revenues from shipments to and from Mexico. Included in the above table are revenues from our Mexico business, which amounted to $673 million and $708 million for the three months ended September 30, 2023 and 2022, respectively, and $2.1 billion and $2.0 billion for the nine months ended September 30, 2023 and 2022, respectively.

Note 14 - Commitments and Contingencies - Environmental Liability Activity (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Balance	$ 253	$ 243
Accruals	85	65
Payments	(75)	(45)
Balance	263	263
Balance, Current	$ 83	$ 64

Note 8 - Accumulated Other Comprehensive Income/Loss

9 Months Ended

Sep. 30, 2023

Comprehensive Income (Loss) Note [Text Block]

8. Accumulated Other Comprehensive Income/Loss

Reclassifications out of accumulated other comprehensive income/loss were as follows (net of tax):

Millions	Defined benefit plans				Foreign currency translation				Unrealized gain on derivative instruments [a]			Total
Balance at July 1, 2023		$	(373	)		$	(160	)		$	16	$	(517	)
Other comprehensive income/(loss) before reclassifications			(1	)			22				-		21
Amounts reclassified from accumulated other comprehensive income/(loss) [b]			(1	)			-				-		(1	)
Net quarter-to-date other comprehensive income/(loss), net of taxes of ($1) million			(2	)			22				-		20
Balance at September 30, 2023		$	(375	)		$	(138	)		$	16	$	(497	)

Balance at July 1, 2022		$	(629	)		$	(212	)		$	-	$	(841	)
Other comprehensive income/(loss) before reclassifications			-				(6	)			-		(6	)
Amounts reclassified from accumulated other comprehensive income/(loss) [b]			15				-				-		15
Net quarter-to-date other comprehensive income/(loss), net of taxes of ($6) million			15				(6	)			-		9
Balance at September 30, 2022		$	(614	)		$	(218	)		$	-	$	(832	)

[a]	Related to interest rate swaps from equity method investments.
[b]	The accumulated other comprehensive income/loss reclassification components are 1) prior service cost/credit and 2) net actuarial loss, which are both included in the computation of net periodic pension benefit/cost. See Note 4 Retirement Plans for additional details.

Millions	Defined benefit plans				Foreign currency translation				Unrealized gain on derivative instruments [a]			Total
Balance at January 1, 2023		$	(378	)		$	(204	)		$	-	$	(582	)
Other comprehensive income/(loss) before reclassifications			5				66				16		87
Amounts reclassified from accumulated other comprehensive income/(loss) [b]			(2	)			-				-		(2	)
Net year-to-date other comprehensive income/(loss), net of taxes of ($4) million			3				66				16		85
Balance at September 30, 2023		$	(375	)		$	(138	)		$	16	$	(497	)

Balance at January 1, 2022		$	(658	)		$	(256	)		$	-	$	(914	)
Other comprehensive income/(loss) before reclassifications			-				38				-		38
Amounts reclassified from accumulated other comprehensive income/(loss) [b]			44				-				-		44
Net year-to-date other comprehensive income/(loss), net of taxes of ($17) million			44				38				-		82
Balance at September 30, 2022		$	(614	)		$	(218	)		$	-	$	(832	)

[a]	Related to interest rate swaps from equity method investments.
[b]	The accumulated other comprehensive income/loss reclassification components are 1) prior service cost/credit and 2) net actuarial loss, which are both included in the computation of net periodic pension benefit/cost. See Note 4 Retirement Plans for additional details.

Note 11 - Accounts Payable and Other Current Liabilities

9 Months Ended

Sep. 30, 2023

Accounts Payable and Accrued Liabilities Disclosure [Text Block]

11. Accounts Payable and Other Current Liabilities

	*Sep. 30,*			Dec. 31,
Millions		*2023*			2022
Accounts payable		$	936		$	784
Income and other taxes payable			701			628
Compensation-related accruals			547			938
Current operating lease liabilities			362			331
Accrued casualty costs			293			242
Interest payable			248			379
Equipment rents payable			99			109
Other			394			431
Total accounts payable and other current liabilities		$	3,580		$	3,842

Note 5 - Other Income (Tables)

9 Months Ended

Sep. 30, 2023

Schedule of Other Nonoperating Income, by Component [Table Text Block]

	Three Months Ended						Nine Months Ended
	September 30,						September 30,
Millions	*2023*			2022			*2023*			2022
Real estate income [a]	$	90		$	103		$	335		$	309
Net periodic pension benefit/(costs)		12			22			40			63
Environmental remediation and restoration		(9	)		(4	)		(31	)		(35	)
Other		13			3			39			(3	)
Total	$	106		$	124		$	383		$	334

Note 9 - Accounts Receivable (Details Textual) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Accounts Receivable, Allowance for Credit Loss, Current	$ 9,000		$ 9,000		$ 10,000
Total Transfer Capacity, Undivided Interests to Investors under Receivables Securitization Facility	800,000		$ 800,000
Receivables Securitization Facility, Duration (Year)			3 years
Value Outstanding, Undivided Interest Held by Investors Under Receivables Securitization Facility	0		$ 0		100,000
Accounts Receivable, Supporting Undivided Investor Held Interest	1,600,000		1,600,000
Interest Expense	334,000	$ 315,000	$ 1,009,000	$ 938,000
Receivables Securitization Facility, Maturity Date			Jul. 31, 2025
Asset-Backed Securities, Securitized Loans and Receivables [Member]
Accounts Receivable, from Securitization, Default or Dilution Ratio			1.00%
Interest Expense	4,000	$ 4,000	$ 8,000	$ 8,000
Maximum [Member]
Total Transfer Capacity, Undivided Interests to Investors under Receivables Securitization Facility	800,000		800,000
Other Assets [Member]
Accounts Receivable, Allowance for Credit Loss, Noncurrent	$ 71,000		$ 71,000		$ 58,000

Note 6 - Income Taxes

9 Months Ended

Sep. 30, 2023

Income Tax Disclosure [Text Block]

6. Income Taxes

In the third quarter of 2023, the states of Iowa, Kansas, and Arkansas enacted legislation to reduce their corporate income tax rates for future years resulting in a $41 million reduction of our deferred tax expense.

In the third quarter of 2022, the states of Iowa, Arkansas, and Idaho enacted legislation to reduce their corporate income tax rates for future years resulting in a $40 million reduction of our deferred tax expense.

In the second quarter of 2023, the state of Nebraska enacted legislation to reduce its corporate income tax rate for future years resulting in a $73 million reduction of our deferred tax expense.

In the second quarter of 2022, the state of Nebraska enacted legislation to reduce its corporate income tax rate for future years resulting in a $55 million reduction of our deferred tax expense.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-14

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 270
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482526/740-270-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 17
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Operating revenues:
Operating revenues	$ 5,941	$ 6,566	$ 17,960	$ 18,695
Operating expenses:
Compensation and benefits	1,201	1,278	3,649	3,471
Fuel	702	932	2,132	2,586
Purchased services and materials	668	626	1,971	1,809
Depreciation	580	563	1,729	1,677
Equipment and other rents	235	215	718	660
Other	378	319	1,086	987
Total operating expenses	3,764	3,933	11,285	11,190
Operating income	2,177	2,633	6,675	7,505
Other income, net (Note 5)	106	124	383	334
Interest expense	(334)	(315)	(1,009)	(938)
Income before income taxes	1,949	2,442	6,049	6,901
Income tax expense (Note 6)	(421)	(547)	(1,322)	(1,541)
Net income	$ 1,528	$ 1,895	$ 4,727	$ 5,360
Share and Per Share (Note 7):
Earnings per share - basic (in dollars per share)	$ 2.51	$ 3.05	$ 7.76	$ 8.56
Earnings per share - diluted (in dollars per share)	$ 2.51	$ 3.05	$ 7.75	$ 8.54
Weighted average number of shares - basic (in shares)	608.7	620.4	609.3	626.1
Weighted average number of shares - diluted (in shares)	609.8	621.5	610.3	627.4
Cargo and Freight [Member]
Operating revenues:
Operating revenues	$ 5,545	$ 6,109	$ 16,770	$ 17,391
Product and Service, Other [Member]
Operating revenues:
Operating revenues	$ 396	$ 457	$ 1,190	$ 1,304

Note 16 - Related Parties

9 Months Ended

Sep. 30, 2023

16. Related Parties

UPRR and other North American railroad companies jointly own TTX Company (TTX). UPRR has a 37.03% economic and voting interest in TTX while the other North American railroads own the remaining interest. In accordance with ASC 323 Investments - Equity Method and Joint Venture, UPRR applies the equity method of accounting to our investment in TTX.

TTX is a rail car pooling company that owns rail cars and intermodal wells to serve North America’s railroads. TTX assists railroads in meeting the needs of their customers by providing rail cars in an efficient, pooled environment. All railroads have the ability to utilize TTX rail cars through car hire by renting rail cars at stated rates.

UPRR had $1.8 billion and $1.7 billion recognized as investments related to TTX in our Condensed Consolidated Statements of Financial Position as of September 30, 2023, and December 31, 2022, respectively. TTX car hire expenses of $101 million and $106 million for the three months ended September 30, 2023 and 2022, respectively, and $306 million and $298 million for the nine months ended September 30, 2023 and 2022, respectively, are included in equipment and other rents in our Condensed Consolidated Statements of Income. In addition, UPRR had accounts payable to TTX of $67 million and $68 million at September 30, 2023, and December 31, 2022, respectively.

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-5

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-6

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(g)(3))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(c))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(e))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//850/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-6

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Note 15 - Share Repurchase Programs (Tables)

9 Months Ended

Sep. 30, 2023

Share Repurchase Program [Table Text Block]

	Number of Shares Purchased					Average Price Paid [a]
		*2023*		2022		*2023*		2022
First quarter [b]			2,908,703		11,014,201	$	203.19	$	249.95
Second quarter [c]			606,581		3,100,683		199.81		232.87
Third quarter			-		9,490,339		-		221.52
Total			3,515,284		23,605,223	$	202.61	$	236.28
Remaining number of shares that may be repurchased under current authority									80,392,027

Note 2 - Operations and Segmentation - Summary of Freight and Other Revenues (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue from Contract with Customer, Excluding Assessed Tax	$ 5,941	$ 6,566	$ 17,960	$ 18,695
Bulk [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	1,766	1,959	5,420	5,604
Industrial [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	2,057	2,194	6,160	6,206
Premium [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	1,722	1,956	5,190	5,581
Cargo and Freight [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	5,545	6,109	16,770	17,391
Other Subsidiary Revenues [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	226	231	681	669
Accessorial Revenues [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	142	212	442	596
Other Miscellaneous Product and Service Revenues [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 28	$ 14	$ 67	$ 39

Note 3 - Stock-based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Outstanding, Options (in shares)	1,974
Outstanding, weighted average exercise price (in dollars per share)	$ 169.64
Outstanding, Weighted-Average Remaining Contractual Term (Year)	6 years 1 month 6 days	6 years
Outstanding, Aggregate Intrinsic Value	$ 66	$ 86
Granted, Options (in shares)	351
Granted, weighted average exercise price (in dollars per share)	$ 202.81
Exercised, Options (in shares)	(165)
Exercised, weighted average exercise price (in dollars per share)	$ 113.97
Forfeited or expired, Options (in shares)	(12)
Forfeited or expired, weighted average exercise price (in dollars per share)	$ 219.18
Outstanding, Options (in shares)	2,148	1,974
Outstanding, weighted average exercise price (in dollars per share)	$ 179.06	$ 169.64
Vested or expected to vest, Options (in shares)	2,128
Vested or expected to vest, weighted average exercise price (in dollars per share)	$ 178.73
Vested or expected to vest, Weighted-Average Remaining Contractual Term (Year)	6 years 1 month 6 days
Vested or expected to vest, Aggregate Intrinsic Value	$ 66
Exercisable, Options (in shares)	1,492
Options, exercisable, Weighted-Average Exercise Price (in dollars per share)	$ 162.93
Options, Exercisable, Weighted-Average Remaining Contractual Term (Year)	5 years
Options, Exercisable, Aggregate Intrinsic Value	$ 65

Note 3 - Stock-based Compensation

9 Months Ended

Sep. 30, 2023

Share-Based Payment Arrangement [Text Block]

3. Stock-Based Compensation

We have several stock-based compensation plans where employees receive nonvested stock options, nonvested retention shares, and nonvested stock units. We refer to the nonvested shares and stock units collectively as “retention awards”. Employees also are able to participate in our employee stock purchase plan (ESPP).

Information regarding stock-based compensation appears in the table below:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
Millions	*2023*		2022		*2023*		2022
Stock-based compensation, before tax:
Stock options	$	4	$	4	$	12	$	11
Retention awards		24		13		57		54
ESPP		4		4		15		12
Total stock-based compensation, before tax	$	32	$	21	$	84	$	77
Excess income tax benefits from equity compensation plans	$	2	$	2	$	9	$	20

Stock Options – Stock options are granted at the closing price on the date of grant, have 10-year contractual terms, and vest no later than 3 years from the date of grant. None of the stock options outstanding at September 30, 2023, are subject to performance or market-based vesting conditions.

The table below shows the annual weighted-average assumptions used for Black-Scholes valuation purposes:

Weighted-Average Assumptions	*2023*			2022
Risk-free interest rate		3.9	%		1.6	%
Dividend yield		2.6	%		1.9	%
Expected life (years)		4.5			4.4
Volatility		29.3	%		28.7	%
Weighted-average grant-date fair value of options granted	$	48.31		$	51.92

The risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant; the expected dividend yield is calculated as the ratio of dividends paid per share of common stock to the stock price on the date of grant; the expected life is based on historical and expected exercise behavior; and expected volatility is based on the historical volatility of our stock price over the expected life of the stock option.

A summary of stock option activity during the nine months ended September 30, 2023, is presented below:

	Options (thous.)		Weighted-Average Exercise Price			Weighted-Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (millions)
Outstanding at January 1, 2023		1,974		$	169.64		6.0		$	86
Granted		351			202.81		N/A			N/A
Exercised		(165	)		113.97		N/A			N/A
Forfeited or expired		(12	)		219.18		N/A			N/A
Outstanding at September 30, 2023		2,148		$	179.06		6.1		$	66
Vested or expected to vest at September 30, 2023		2,128		$	178.73		6.1		$	66
Options exercisable at September 30, 2023		1,492		$	162.93		5.0		$	65

At September 30, 2023, there was $20 million of unrecognized compensation expense related to nonvested stock options, which is expected to be recognized over a weighted-average period of 1.3 years. Additional information regarding stock option exercises appears in the following table:

	Three Months Ended						Nine Months Ended
	September 30,						September 30,
Millions	*2023*			2022			*2023*			2022
Intrinsic value of stock options exercised	$	10		$	7		$	17		$	51
Cash received from option exercises		9			7			17			24
Treasury shares repurchased for employee payroll taxes		(1	)		(2	)		(3	)		(7	)
Income tax benefit realized from option exercises		2			1			4			7
Aggregate grant-date fair value of stock options vested		-			-			14			13

Retention Awards – Retention awards are granted at no cost to the employee, vest over periods lasting up to 4 years, and dividends and dividend equivalents are paid to participants during the vesting periods.

Changes in our retention awards during the nine months ended September 30, 2023, were as follows:

	Shares (thous.)		Weighted-Average Grant-Date Fair Value
Nonvested at January 1, 2023		1,069		$	196.47
Granted		296			202.83
Vested		(305	)		163.27
Forfeited		(39	)		205.35
Nonvested at September 30, 2023		1,021		$	207.89

At September 30, 2023, there was $98 million of total unrecognized compensation expense related to nonvested retention awards, which is expected to be recognized over a weighted-average period of 1.6 years.

Performance Retention Awards – In February 2023, our Board of Directors approved performance stock unit grants. The basic terms of these performance stock units are identical to those granted in February 2022, including the annual return on invested capital (ROIC) and operating income growth (OIG) performance targets. The OIG performance targets compare to companies in the S&P 100 Industrials Index plus the Class I railroads. We define ROIC as net operating profit adjusted for interest expense (including interest on average operating lease liabilities) and taxes on interest divided by average invested capital adjusted for average operating lease liabilities.

The February 2023 stock units awarded to selected employees are subject to continued employment for 37 months, the attainment of certain levels of ROIC, and the relative three-year OIG. We expense two-thirds of the fair value of the units that are probable of being earned based on our forecasted ROIC over the three-year performance period, and with respect to the third year of the plan, the remaining one-third of the fair value is subject to the relative three-year OIG. We measure the fair value of performance stock units based upon the closing price of the underlying common stock as of the date of grant. Dividend equivalents are accumulated during the service period and paid to participants only after the units are earned.

Changes in our performance retention awards during the nine months ended September 30, 2023, were as follows:

	Shares (thous.)		Weighted-Average Grant-Date Fair Value
Nonvested at January 1, 2023		594		$	199.82
Granted		251			202.81
Vested		(78	)		189.24
Unearned		(127	)		186.11
Forfeited		(13	)		220.23
Nonvested at September 30, 2023		627		$	204.69

At September 30, 2023, there was $16 million of total unrecognized compensation expense related to nonvested performance retention awards, which is expected to be recognized over a weighted-average period of 1.1 years. This expense is subject to achievement of the performance measures established for the performance stock unit grants.

Note 7 - Earnings Per Share

9 Months Ended

Sep. 30, 2023

Earnings Per Share [Text Block]

7. Earnings Per Share

The following table provides a reconciliation between basic and diluted earnings per share:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
Millions, Except Per Share Amounts	*2023*		2022		*2023*		2022
Net income	$	1,528	$	1,895	$	4,727	$	5,360
Weighted-average number of shares outstanding:
Basic		608.7		620.4		609.3		626.1
Dilutive effect of stock options		0.4		0.5		0.4		0.7
Dilutive effect of retention shares and units		0.7		0.6		0.6		0.6
Diluted		609.8		621.5		610.3		627.4
Earnings per share – basic	$	2.51	$	3.05	$	7.76	$	8.56
Earnings per share – diluted	$	2.51	$	3.05	$	7.75	$	8.54
Stock options excluded as their inclusion would be anti-dilutive		1.0		0.3		0.9		0.3

Note 14 - Commitments and Contingencies (Tables)

9 Months Ended

Sep. 30, 2023

Schedule of Loss Contingencies by Contingency, Environmental [Table Text Block]

Millions, for the Nine Months Ended September 30,	*2023*			2022
Beginning balance	$	253		$	243
Accruals		85			65
Payments		(75	)		(45	)
Ending balance at September 30,	$	263		$	263
Current portion, ending balance at September 30,	$	83		$	64

Personal Injury [Member]

Schedule of Loss Contingencies by Contingency [Table Text Block]

Millions, for the Nine Months Ended September 30,	*2023*			2022
Beginning balance	$	361		$	325
Current year accruals		81			79
Changes in estimates for prior years		55			36
Payments		(104	)		(93	)
Ending balance at September 30,	$	393		$	347
Current portion, ending balance at September 30,	$	105		$	77

Note 13 - Debt - Schedule of Unsecured Debt (Details) - Unsecured Debt [Member] $ in Billions	Sep. 30, 2023 USD ($)
The 4.750% Notes, Due February 21, 2026 [Member]
Debt Instrument	$ 0.5
The 4.950% Notes, Due May 15, 2053 [Member]
Debt Instrument	$ 0.5

Note 7 - Earnings Per Share (Tables)

9 Months Ended

Sep. 30, 2023

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
Millions, Except Per Share Amounts	*2023*		2022		*2023*		2022
Net income	$	1,528	$	1,895	$	4,727	$	5,360
Weighted-average number of shares outstanding:
Basic		608.7		620.4		609.3		626.1
Dilutive effect of stock options		0.4		0.5		0.4		0.7
Dilutive effect of retention shares and units		0.7		0.6		0.6		0.6
Diluted		609.8		621.5		610.3		627.4
Earnings per share – basic	$	2.51	$	3.05	$	7.76	$	8.56
Earnings per share – diluted	$	2.51	$	3.05	$	7.75	$	8.54
Stock options excluded as their inclusion would be anti-dilutive		1.0		0.3		0.9		0.3

Note 15 - Share Repurchase Programs - Schedule of Share Repurchase Programs (Details) - $ / shares

3 Months Ended

9 Months Ended

18 Months Ended

36 Months Ended

Sep. 30, 2023

Jun. 30, 2023

Mar. 31, 2023

Sep. 30, 2022

Jun. 30, 2022

^[1]

Mar. 31, 2022

^[2]

Sep. 30, 2023

Sep. 30, 2022

Sep. 30, 2023

Mar. 31, 2022

Treasury Stock, Number of Shares Purchased (in shares)

606,581

2,908,703

9,490,339

3,100,683

11,014,201

3,515,284

23,605,223

19,600,000

83,300,000

Treasury Stock, Average Price per Share (in dollars per share)

$ 0

$ 199.81

$ 203.19

$ 221.52

$ 232.87

^[3]

$ 249.95

^[3]

$ 202.61

$ 236.28

Remaining number of shares that may be repurchased under current authority (in shares)

80,392,027

[1]	Includes 1,847,185 shares repurchased in 2022 under accelerated share repurchase programs.
[2]	Includes 7,012,232 shares repurchased in 2022 under accelerated share repurchase programs.
[3]	In the period of the final settlement, the average price paid under the accelerated share repurchase programs is calculated based on the total program value less the value assigned to the initial delivery of shares. The average price of the completed 2022 accelerated share repurchase programs was $248.32.

Note 4 - Retirement Plans (Tables)

9 Months Ended

Sep. 30, 2023

Schedule of Net Benefit Costs [Table Text Block]

	Three Months Ended						Nine Months Ended
	September 30,						September 30,
Millions	*2023*			2022			*2023*			2022
Service cost	$	13		$	21		$	38		$	73
Interest cost		48			31			140			93
Expected return on plan assets		(62	)		(74	)		(186	)		(220	)
Amortization of actuarial loss		2			21			6			64
Net periodic pension (benefit)/cost	$	1		$	(1	)	$	(2	)	$	10

Note 4 - Retirement Plans

9 Months Ended

Sep. 30, 2023

Retirement Benefits [Text Block]

4. Retirement Plans

We provide defined benefit retirement income to eligible non-union employees through qualified and non-qualified (supplemental) pension plans. Qualified and non-qualified pension benefits are based on years of service and the highest compensation during the latest years of employment, with specific reductions made for early retirements. Non-union employees hired on or after January 1, 2018, are no longer eligible for pension benefits, but are eligible for an enhanced 401(k) plan.

Expense

Pension expense is determined based upon the annual service cost of benefits (the actuarial cost of benefits earned during a period) and the interest cost on those liabilities, less the expected return on plan assets. The expected long-term rate of return on plan assets is applied to a calculated value of plan assets that recognizes changes in fair value over a 5-year period. This practice is intended to reduce year-to-year volatility in pension expense, but it can have the effect of delaying the recognition of differences between actual returns on assets and expected returns based on long-term rate of return assumptions. Differences in actual experience in relation to assumptions are not recognized in net income immediately but are deferred in accumulated other comprehensive income/loss and, if necessary, amortized as pension expense.

The components of our net periodic pension benefit/cost were as follows:

	Three Months Ended						Nine Months Ended
	September 30,						September 30,
Millions	*2023*			2022			*2023*			2022
Service cost	$	13		$	21		$	38		$	73
Interest cost		48			31			140			93
Expected return on plan assets		(62	)		(74	)		(186	)		(220	)
Amortization of actuarial loss		2			21			6			64
Net periodic pension (benefit)/cost	$	1		$	(1	)	$	(2	)	$	10

Cash Contributions

For the nine months ended September 30, 2023, cash contributions totaled $0 to the qualified pension plans. Any contributions made during 2023 will be based on cash generated from operations and financial market considerations. Our policy with respect to funding the qualified pension plans is to fund at least the minimum required by law and not more than the maximum amount deductible for tax purposes. At September 30, 2023, we do not have minimum cash funding requirements for 2023.

The entire disclosure for retirement benefits.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 70
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480794/715-70-50-1

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480482/715-20-55-17

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)(iv)(03)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (q)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (l)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//715/tableOfContent

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)(iii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (o)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (p)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (r)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (r)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480126/715-20-S99-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 60
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480266/715-60-50-3

Note 3 - Stock-based Compensation - Additional Information Regarding Stock Option Exercises (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Intrinsic value of stock options exercised	$ 10	$ 7	$ 17	$ 51
Cash received from option exercises	9	7	17	24
Treasury shares repurchased for employee payroll taxes	(1)	(2)	(3)	(7)
Income tax benefit realized from option exercises	2	1	4	7
Aggregate grant-date fair value of stock options vested	$ 0	$ 0	$ 14	$ 13

Note 11 - Accounts Payable and Other Current Liabilities - Schedule of Accounts Payable and Other Current Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Accounts payable	$ 936	$ 784
Income and other taxes payable	701	628
Compensation-related accruals	547	938
Accrued casualty costs	293	242
Interest payable	248	379
Other	394	431
Total accounts payable and other current liabilities	3,580	3,842
Equipment [Member]
Equipment rents payable	99	109
Accounts payable and Other Current Liabilities [Member]
Current operating lease liabilities	$ 362	$ 331

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($)
$ in Millions

3 Months Ended

9 Months Ended

Sep. 30, 2023

Sep. 30, 2022

Sep. 30, 2023

Sep. 30, 2022

Foreign currency translation

$ 1,528

$ 1,895

$ 4,727

$ 5,360

Other comprehensive income/(loss):

Defined benefit plans

(2)

(6)

Unrealized gain on derivative instruments

^[1]

^[2]

Comprehensive income

1,548

1,904

4,812

5,442

$ 1,528

$ 1,895

$ 4,727

$ 5,360

[1]	Net of deferred taxes of ($1) million and ($6) million during the three months ended September 30, 2023 and 2022, respectively.
[2]	Net of deferred taxes of ($4) million and ($17) million during the nine months ended September 30, 2023 and 2022, respectively.

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

Note 4 - Retirement Plans (Details Textual) $ in Thousands	9 Months Ended
Note 4 - Retirement Plans (Details Textual) $ in Thousands	Sep. 30, 2023 USD ($)
Defined Benefit Plan, Expected Return on Plan Assets, Changes In Fair Value, Period (Year)	5 years
Payment for Pension Benefits	$ 0

Note 13 - Debt (Details Textual) - USD ($) $ in Thousands	9 Months Ended
Note 13 - Debt (Details Textual) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Feb. 03, 2022
Proceeds from Issuance of Commercial Paper	$ 1,400,000
Repayments of Commercial Paper	$ 1,300,000
Commercial Paper, Maturity Duration, Minimum (Day)	11 days
Commercial Paper Maturity Duration, Maximum (Day)	88 days
Commercial Paper	$ 302,000
Board of Directors Authorized Debt Issuance			$ 12,000,000
Board of Directors Remaining Debt Issuance	5,600,000
Secured Debt [Member]
Long-Term Debt, Gross	$ 0	$ 100,000
Commercial Paper [Member]
Debt, Weighted Average Interest Rate	5.40%
Revolving Credit Facility [Member]
Line of Credit Facility, Remaining Borrowing Capacity	$ 2,000,000
Long-Term Line of Credit, Total	$ 0
Line of Credit Facility, Expiration Date	May 20, 2027
Allowable Debt Per Debt to Net Worth Coverage Ratio as Defined Facility	$ 44,300,000
Outstanding Debt as Defined by Facility	34,600,000
Cross Default Provision as Defined By Facility	$ 150,000

Note 14 - Commitments and Contingencies

9 Months Ended

Sep. 30, 2023

Commitments Contingencies and Guarantees [Text Block]

14. Commitments and Contingencies

Asserted and Unasserted Claims – Various claims and lawsuits are pending against us and certain of our subsidiaries. We cannot fully determine the effect of all asserted and unasserted claims on our consolidated results of operations, financial condition, or liquidity. To the extent possible, we have recorded a liability where asserted and unasserted claims are considered probable and where such claims can be reasonably estimated. We currently do not expect that any known lawsuits, claims, environmental costs, commitments, contingent liabilities, or guarantees will have a material adverse effect on our consolidated results of operations, financial condition, or liquidity after taking into account liabilities and insurance recoveries previously recorded for these matters.

In December 2019, we received a putative class action complaint under the Illinois Biometric Information Privacy Act, alleging violation due to the use of a finger scan system developed and managed by third parties. Union Pacific and the plaintiff are currently in the discovery phase. While we believe that we have strong defenses to the claims made in the complaint and will vigorously defend ourselves, there is no assurance regarding the ultimate outcome. Therefore, the outcome of this litigation is inherently uncertain, and we cannot reasonably estimate any loss or range of loss that may arise from this matter.

Personal Injury – The Federal Employers’ Liability Act (FELA) governs compensation for work-related accidents. Under FELA, damages are assessed based on a finding of fault through litigation or out-of-court settlements. We offer a comprehensive variety of services and rehabilitation programs for employees who are injured at work.

Approximately 94% of the recorded liability is related to asserted claims and approximately 6% is related to unasserted claims at September 30, 2023. Because of the uncertainty surrounding the ultimate outcome of personal injury claims, it is reasonably possible that future costs to settle these claims may range from approximately $393 million to $503 million. We record an accrual at the low end of the range as no amount of loss within the range is more probable than any other. Estimates can vary over time due to evolving trends in litigation.

Our personal injury liability activity was as follows:

Millions, for the Nine Months Ended September 30,	*2023*			2022
Beginning balance	$	361		$	325
Current year accruals		81			79
Changes in estimates for prior years		55			36
Payments		(104	)		(93	)
Ending balance at September 30,	$	393		$	347
Current portion, ending balance at September 30,	$	105		$	77

Environmental Costs – We are subject to federal, state, and local environmental laws and regulations. We have identified 338 sites where we are or may be liable for remediation costs associated with alleged contamination or for violations of environmental requirements. This includes32 sites that are the subject of actions taken by the U.S. government, including 20 that are currently on the Superfund National Priorities List. Certain federal legislation imposes joint and several liability for the remediation of identified sites; consequently, our ultimate environmental liability may include costs relating to activities of other parties, in addition to costs relating to our own activities at each site.

Our environmental liability activity was as follows:

Millions, for the Nine Months Ended September 30,	*2023*			2022
Beginning balance	$	253		$	243
Accruals		85			65
Payments		(75	)		(45	)
Ending balance at September 30,	$	263		$	263
Current portion, ending balance at September 30,	$	83		$	64

The environmental liability includes future costs for remediation and restoration of sites, as well as ongoing monitoring costs, but excludes any anticipated recoveries from third-parties. Cost estimates are based on information available for each site, financial viability of other potentially responsible parties, and existing technology, laws, and regulations. The ultimate liability for remediation is difficult to determine because of the number of potentially responsible parties, site-specific cost sharing arrangements with other potentially responsible parties, the degree of contamination by various wastes, the scarcity and quality of volumetric data related to many of the sites, and the speculative nature of remediation costs. Estimates of liability may vary over time due to changes in federal, state, and local laws governing environmental remediation. Current obligations are not expected to have a material adverse effect on our consolidated results of operations, financial condition, or liquidity.

Insurance – The Company has a consolidated, wholly-owned captive insurance subsidiary (the Captive), that provides insurance coverage for certain risks including general liability, property, cyber, and FELA claims that are subject to reinsurance. The Captive receives direct premiums, which are netted against the Company’s premium costs in other expenses in the Condensed Consolidated Statements of Income. We record both liabilities and reinsurance receivables using an actuarial analysis based on historical experience in our Condensed Consolidated Statements of Financial Position.

Indemnities – Our maximum potential exposure under indemnification arrangements, including certain tax indemnifications, can range from a specified dollar amount to an unlimited amount, depending on the nature of the transactions and the agreements. Due to uncertainty as to whether claims will be made or how they will be resolved, we cannot reasonably determine the probability of an adverse claim or reasonably estimate any adverse liability or the total maximum exposure under these indemnification arrangements. We do not have any reason to believe that we will be required to make any material payments under these indemnity provisions.

Note 16 - Related Parties (Details Textual) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Accounts Payable, Current	$ 936		$ 936		$ 784
UPRR [Member] \| TTX Company [Member]
Accounts Payable, Current	$ 67		$ 67		68
TTX Company [Member] \| UPRR [Member]
Equity Method Investment, Ownership Percentage	37.03%		37.03%
Equity Method Investments	$ 1,800		$ 1,800		$ 1,700
TTX Company [Member] \| UPRR [Member] \| Car Hire Expenses [Member]
Other Expenses	$ 101	$ 106	$ 306	$ 298

Note 10 - Properties

9 Months Ended

Sep. 30, 2023