CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
OPERATING REVENUE	$ 5,647	$ 5,945
OPERATING EXPENSES
Cost of services and products (exclusive of depreciation and amortization)	2,520	2,803
Selling, general and administrative	932	1,109
Depreciation and amortization	1,188	1,283
Goodwill impairment	6,506	0
Total operating expenses	11,146	5,195
OPERATING (LOSS) INCOME	(5,499)	750
OTHER (EXPENSE) INCOME
Interest expense	(523)	(535)
Other (expense) income, net	(5)	21
Total other expense, net	(528)	(514)
INCOME (LOSS) BEFORE INCOME TAX EXPENSE	(6,027)	236
Income tax expense	138	121
NET (LOSS) INCOME	$ (6,165)	$ 115
BASIC AND DILUTED (LOSS) EARNINGS PER COMMON SHARE
BASIC (in dollars per share)	$ (5.77)	$ 0.11
DILUTED (in dollars per share)	$ (5.77)	$ 0.11
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING
BASIC (in shares)	1,068,878	1,065,796
DILUTED (in shares)	1,068,878	1,069,183