Condensed Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating revenues:
Revenue from contract with customer excluding assessed tax	$ 5,166	$ 4,596	$ 14,947	$ 13,448
Total operating revenues	5,566	4,919	16,071	14,392
Operating expenses:
Compensation and benefits	1,040	1,008	3,088	2,972
Depreciation	553	555	1,652	1,653
Purchased services and materials	510	508	1,478	1,470
Fuel	544	301	1,452	982
Equipment and other rents	217	217	629	655
Other	270	299	874	832
Total operating expenses	3,134	2,888	9,173	8,564
Operating income	2,432	2,031	6,898	5,828
Other income (Note 6)	38	37	214	221
Interest expense	(290)	(295)	(862)	(862)
Income before income taxes	2,180	1,773	6,250	5,187
Income taxes (Note 7)	(507)	(410)	(1,438)	(1,218)
Net income	$ 1,673	$ 1,363	$ 4,812	$ 3,969
Share and Per Share (Note 8):
Earnings per share - basic	$ 2.58	$ 2.02	$ 7.31	$ 5.85
Earnings per share - diluted	$ 2.57	$ 2.01	$ 7.29	$ 5.83
Weighted average number of shares - basic	648.7	675.0	658.3	679.0
Weighted average number of shares - diluted	650.3	676.8	659.9	680.7
Cargo and Freight [Member]
Operating revenues:
Revenue from contract with customer excluding assessed tax	$ 5,166	$ 4,596	$ 14,947	$ 13,448
Other [Member]
Operating revenues:
Revenue from contract with customer excluding assessed tax	$ 400	$ 323	$ 1,124	$ 944