Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Activities
Net income	$ 5,087	$ 5,946	$ 5,990
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	2,625	2,528	2,456
Deferred income taxes	99	10	446
Other, net	(169)	(56)	(2,635)
Changes in current assets and liabilities:
Accounts receivable, net	(100)	(88)	(73)
Materials and supplies	(46)	(88)	(61)
Other current assets	173	111	50
Accounts payable and other current liabilities	(370)	388	336
Net cash provided by operating activities	7,299	8,751	6,509
Investing Activities
Capital expenditures excluding equipment	(3,497)	(3,355)	(2,735)
Acquisition of equipment	(423)	(177)	(174)
Purchases of investments and investments in time deposits	(24)	(23)	0
Proceeds from sales of investments and maturities of time deposits	0	0	1
Other, net	(68)	(69)	(17)
Net cash used for investing activities	(4,012)	(3,624)	(2,925)
Financing Activities
Proceeds from issuance of long-term debt	1,600	1,000	1,550
Payments on long-term debt and finance leases	(1,562)	(932)	(1,543)
Cash distributions	(3,100)	(5,000)	(3,800)
Other, net	(15)	(15)	(19)
Net cash used for financing activities	(3,077)	(4,947)	(3,812)
Increase (decrease) in cash and cash equivalents	210	180	(228)
Cash and cash equivalents:
Beginning of period	1,938	1,758	1,986
End of period	2,148	1,938	1,758
Supplemental Cash Flow Information
Interest paid, net of amounts capitalized	1,047	1,020	1,032
Capital investments accrued but not yet paid	469	307	238
Income taxes paid, net of refunds	1,358	1,749	1,386
Non-cash asset financing	$ 0	$ 176	$ 16