Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating Activities
Net income	$ 1,247	$ 1,371
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	647	627
Deferred income taxes	71	(122)
Other, net	(47)	(76)
Changes in current assets and liabilities:
Accounts receivable, net	(19)	(83)
Materials and supplies	18	(116)
Other current assets	(35)	(14)
Accounts payable and other current liabilities	(431)	472
Net cash provided by operating activities	1,451	2,059
Investing Activities
Capital expenditures excluding equipment	(679)	(598)
Acquisition of equipment	(16)	(18)
Purchases of investments and investments in time deposits	(15)	0
Other, net	(134)	(70)
Net cash used in investing activities	(844)	(686)
Financing Activities
Payments on long-term debt and finance leases	(708)	(202)
Cash distributions	0	(1,000)
Net cash used in financing activities	(708)	(1,202)
Increase (decrease) in cash and cash equivalents	(101)	171
Cash and cash equivalents:
Beginning of period	1,938	1,758
End of period	1,837	1,929
Supplemental Cash Flow Information
Interest paid, net of amounts capitalized	300	290
Capital investments accrued but not yet paid	172	141
Income taxes paid, net of refunds	8	5
Non-cash asset financing	$ 0	$ 1