Condensed Consolidated Statement of Equity - USD ($) shares in Millions, $ in Millions		Total	Common Stock [Member]	6.875% Mandatory Convertible Preferred Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Foreign Currency Adjustment Attributable to Parent [Member]	Dividends/Distributions in Excess of Earnings [Member]
Balance, shares Period Start at Dec. 31, 2018			415
Balance, value Period Start at Dec. 31, 2018		$ 11,571	$ 4	$ 0	$ 17,767	$ (5)	$ (6,195)
Preferred Stock, Shares Outstanding Period Start at Dec. 31, 2018				2
Stock-based compensation related activity, net of forfeitures, value		45			45
Stock-based compensation related activity, net of forfeitures, shares			1
Purchases and retirement of common stock, value		(42)			(42)
Stock Issued During Period, Shares, New Issues			0
Stock Issued During Period, Value, New Issues		0			0
Common stock dividends/distributions	[1]	(472)					(472)
Dividends/distributions on preferred stock	[1]	(28)					(28)
Foreign currency translation adjustments		0				0
Net income (loss)		193					193
Balance, shares Period End at Mar. 31, 2019			416
Balance, value Period End at Mar. 31, 2019		$ 11,267	$ 4	$ 0	17,770	(5)	(6,502)
Preferred Stock, Shares Outstanding Period End at Mar. 31, 2019				2
Balance, shares Period Start at Dec. 31, 2019		416	416
Balance, value Period Start at Dec. 31, 2019		$ 10,489	$ 4	$ 0	17,855	(5)	(7,365)
Preferred Stock, Shares Outstanding Period Start at Dec. 31, 2019		2		2
Stock-based compensation related activity, net of forfeitures, value		$ 53			53
Stock-based compensation related activity, net of forfeitures, shares			1
Purchases and retirement of common stock, value		(73)			(73)
Other Comprehensive Income (Loss), Net of Tax	[2]	(1)				(1)
Common stock dividends/distributions	[1]	(504)					(504)
Dividends/distributions on preferred stock	[1]	(28)					(28)
Foreign currency translation adjustments		(1)
Net income (loss)		$ 185					185
Balance, shares Period End at Mar. 31, 2020		417	417
Balance, value Period End at Mar. 31, 2020		$ 10,121	$ 4	$ 0	$ 17,835	$ (6)	$ (7,712)
Preferred Stock, Shares Outstanding Period End at Mar. 31, 2020		2		2

[1] See note 8 for information regarding common and preferred stock dividends declared per share.

[2] See the condensed consolidated statement of operations and other comprehensive income (loss) for the components of other comprehensive income (loss).