CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
OPERATING ACTIVITIES
Net income (loss)	$ 2,033	$ (1,232)	$ (5,269)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	4,019	4,710	4,829
Goodwill impairment	0	2,642	6,506
Deferred income taxes	598	366	440
Provision for uncollectible accounts	105	189	145
Net (gain) loss on early retirement and modification of debt	(8)	105	(72)
Stock-based compensation	120	175	162
Changes in current assets and liabilities:
Accounts receivable	(8)	115	(5)
Accounts payable	(261)	(543)	(261)
Accrued income and other taxes	(69)	27	20
Other current assets and liabilities, net	(353)	(262)	(32)
Retirement benefits	163	(111)	(12)
Changes in other noncurrent assets and liabilities, net	283	246	245
Other, net	(121)	97	(16)
Net cash provided by operating activities	6,501	6,524	6,680
INVESTING ACTIVITIES
Capital expenditures	(2,900)	(3,729)	(3,628)
Proceeds from sale of property, plant and equipment and other assets	135	153	93
Other, net	53	12	(35)
Net cash used in investing activities	(2,712)	(3,564)	(3,570)
FINANCING ACTIVITIES
Net proceeds from issuance of long-term debt	1,881	4,361	3,707
Payments of long-term debt	(3,598)	(7,315)	(4,157)
Net proceeds from (payments on) revolving line of credit	50	(100)	(300)
Dividends paid	(1,087)	(1,109)	(1,100)
Repurchases of common stock	(1,000)	0	0
Other, net	(53)	(87)	(61)
Net cash used in financing activities	(3,807)	(4,250)	(1,911)
Net (decrease) increase in cash, cash equivalents and restricted cash	(18)	(1,290)	1,199
Cash, cash equivalents and restricted cash at beginning of period	427	1,717	518
Cash, cash equivalents and restricted cash at end of period	409	427	1,717
Supplemental cash flow information:
Income taxes (paid) refunded, net	(112)	28	34
Interest paid (net of capitalized interest of $53, $75 and $72)	(1,487)	(1,627)	(2,028)
Supplemental non-cash information regarding investing activities:
Sale of property, plant and equipment in exchange for note receivable	56	0	0
Supplemental non-cash information regarding financing activities:
Purchase of software subscription in exchange for installment debt	77	0	0
Cash, cash equivalents and restricted cash:
Cash and cash equivalents	354	406	1,690
Cash and cash equivalents included in Assets held for sale	40	0	0
Restricted cash included in Other current assets	2	3	3
Restricted cash included in Other, net noncurrent assets	13	18	24
Total	$ 409	$ 427	$ 1,717