CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	COMMON STOCK	ADDITIONAL PAID-IN CAPITAL	ACCUMULATED OTHER COMPREHENSIVE LOSS	RETAINED EARNINGS (ACCUMULATED DEFICIT)
Balance at beginning of period at Dec. 31, 2016		$ 547	$ 14,970	$ (2,117)	$ (1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	$ 1,389				1,389
Issuance of common stock to acquire Level 3, including replacement of Level 3's share-based compensation awards		517	9,462
Issuance of common stock through dividend reinvestment, incentive and benefit plans		5
Shares withheld to satisfy tax withholdings			(20)
Share-based compensation and other, net			79
Dividends declared			(1,177)		(288)
Other comprehensive (loss) income	122			122
Balance at end of period at Dec. 31, 2017	$ 23,491	1,069	23,314	(1,995)	1,103
Increase (Decrease) in Stockholders' Equity [Roll Forward]
DIVIDENDS DECLARED PER COMMON SHARE (usd per share)	$ 2.16
Cumulative effect of adoption of ASU | Accounting Standards Update 2016-09					3
Net (loss) income	$ (1,733)				(1,733)
Issuance of common stock to acquire Level 3, including replacement of Level 3's share-based compensation awards			(2)
Issuance of common stock through dividend reinvestment, incentive and benefit plans		11
Shares withheld to satisfy tax withholdings			(56)
Share-based compensation and other, net			187
Dividends declared			(586)		(1,758)
Acquisition of additional minority interest in a subsidiary			(5)
Other comprehensive (loss) income	(59)			(59)
Balance at end of period at Dec. 31, 2018	$ 19,828	1,080	22,852	(2,461)	(1,643)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
DIVIDENDS DECLARED PER COMMON SHARE (usd per share)	$ 2.16
Cumulative effect of adoption of ASU | Accounting Standards Update 2018-02	$ (407)			(407)	407
Cumulative effect of adoption of ASU | Accounting Standards Update 2014-09					338
Net (loss) income	(5,269)				(5,269)
Issuance of common stock through dividend reinvestment, incentive and benefit plans		10
Shares withheld to satisfy tax withholdings			(37)
Share-based compensation and other, net			163
Dividends declared			(1,104)		2
Other comprehensive (loss) income	(219)			(219)
Balance at end of period at Dec. 31, 2019	$ 13,470	$ 1,090	$ 21,874	$ (2,680)	(6,814)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
DIVIDENDS DECLARED PER COMMON SHARE (usd per share)	$ 1.00
Cumulative effect of adoption of ASU | Accounting Standards Update 2016-02					$ 96