CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
OPERATING REVENUE	$ 4,676	$ 5,029
OPERATING EXPENSES
Cost of services and products (exclusive of depreciation and amortization)	1,985	2,136
Selling, general and administrative	800	756
Depreciation and amortization	808	1,150
Total operating expenses	3,593	4,042
OPERATING INCOME	1,083	987
OTHER (EXPENSE) INCOME
Interest expense	(352)	(389)
Other income, net	70	34
Total other expense, net	(282)	(355)
INCOME BEFORE INCOME TAXES	801	632
Income tax expense	202	157
NET INCOME	$ 599	$ 475
BASIC AND DILUTED EARNINGS PER COMMON SHARE
BASIC (in dollars per share)	$ 0.59	$ 0.44
DILUTED (in dollars per share)	$ 0.59	$ 0.44
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING
BASIC (in shares)	1,008,430	1,082,474
DILUTED (in shares)	1,015,215	1,091,586