CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	COMMON STOCK	ADDITIONAL PAID-IN CAPITAL	ACCUMULATED OTHER COMPREHENSIVE LOSS	ACCUMULATED DEFICIT
Balance at beginning of period at Dec. 31, 2018		$ 1,080	$ 22,852	$ (2,461)	$ (1,643)
Increase (Decrease) in Stockholders' Equity
Issuance of common stock through dividend reinvestment, incentive and benefit plans		10
Shares withheld to satisfy tax withholdings			(26)
Share-based compensation and other, net			34
Dividends declared			(285)
Other comprehensive (loss) income	$ 32			32
Net income (loss)	(6,165)				(6,165)
Balance at end of period at Mar. 31, 2019	$ 13,524	1,090	22,575	(2,429)	(7,712)
Increase (Decrease) in Stockholders' Equity
DIVIDENDS DECLARED PER COMMON SHARE (in dollars per share)	$ 0.25
Balance at beginning of period at Dec. 31, 2019	$ 13,470	1,090	21,874	(2,680)	(6,814)
Increase (Decrease) in Stockholders' Equity
Issuance of common stock through dividend reinvestment, 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) income	(275)			(275)
Net income (loss)	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