CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Statement [Abstract]
OPERATING REVENUE	$ 4,612	$ 4,924	$ 9,288	$ 9,953
OPERATING EXPENSES
Cost of services and products (exclusive of depreciation and amortization)	2,058	2,115	4,043	4,251
Selling, general and administrative	815	762	1,615	1,518
Depreciation and amortization	827	1,041	1,635	2,191
Total operating expenses	3,700	3,918	7,293	7,960
OPERATING INCOME	912	1,006	1,995	1,993
OTHER (EXPENSE) INCOME
Interest expense	(337)	(384)	(689)	(773)
Other (expense) income, net	(122)	52	(52)	86
Total other expense, net	(459)	(332)	(741)	(687)
INCOME BEFORE INCOME TAXES	453	674	1,254	1,306
Income tax expense	109	168	311	325
NET INCOME	$ 344	$ 506	$ 943	$ 981
BASIC AND DILUTED EARNINGS PER COMMON SHARE
BASIC (in dollars per share)	$ 0.34	$ 0.47	$ 0.93	$ 0.90
DILUTED (in dollars per share)	$ 0.34	$ 0.46	$ 0.93	$ 0.90
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING
BASIC (in shares)	1,012,943	1,086,453	1,010,686	1,084,464
DILUTED (in shares)	1,016,620	1,093,402	1,015,917	1,092,494