CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	COMMON STOCK	ADDITIONAL PAID-IN CAPITAL	ACCUMULATED OTHER COMPREHENSIVE LOSS	ACCUMULATED DEFICIT	ACCUMULATED DEFICIT Cumulative Effect, Period of Adoption, Adjustment
Balance at beginning of period at Dec. 31, 2019		$ 1,090	$ 21,874	$ (2,680)	$ (6,814)	$ 9
Increase (Decrease) in Stockholders' Equity
Issuance of common stock through incentive and benefit plans		8
Shares withheld to satisfy tax withholdings			(33)
Share-based compensation and other, net			79
Dividends declared			(286)
Other comprehensive loss	$ (275)			(275)
Net income	314				314
Other					5
Balance at end of period at Mar. 31, 2020	$ 13,291	1,098	21,634	(2,955)	(6,486)
Increase (Decrease) in Stockholders' Equity
DIVIDENDS DECLARED PER COMMON SHARE (in dollars per share)	$ 0.25
Balance at beginning of period at Dec. 31, 2020	$ 11,162	1,097	20,909	(2,813)	(8,031)
Increase (Decrease) in Stockholders' Equity
Issuance of common stock through incentive and benefit plans		9
Shares withheld to satisfy tax withholdings			(39)
Share-based compensation and other, net			20
Dividends declared			(292)
Other comprehensive loss	(32)			(32)
Net income	475				475
Other					0
Balance at end of period at Mar. 31, 2021	$ 11,303	$ 1,106	$ 20,598	$ (2,845)	$ (7,556)
Increase (Decrease) in Stockholders' Equity
DIVIDENDS DECLARED PER COMMON SHARE (in dollars per share)	$ 0.25