Consolidated Statement of Convertible Preferred Stock and Equity - USD ($) shares in Millions, $ in Millions		Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital	Foreign Currency Translation Adjustments	Dividends/Distributions in Excess of Earnings	Common Class A [Member]	Common Class A [Member] Common Stock [Member]	Common Class A [Member] Additional Paid-in Capital	6.875% Mandatory Convertible Preferred Stock [Member]	6.875% Mandatory Convertible Preferred Stock [Member] Preferred Stock [Member]	6.875% Mandatory Convertible Preferred Stock [Member] Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Convertible Preferred Stock, shares outstanding			0
Accumulated other Comprehensive Income (Loss), Net of Tax						$ (6)
Balance, value at Dec. 31, 2016		$ 7,222	$ 0	$ 4	$ 10,938		$ (3,714)
Balance, (in shares) at Dec. 31, 2016				361
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation related activity, net of forfeitures, value		100			100
Stock-based compensation related activity, net of forfeitures, shares				1
Purchases and retirement of capital stock, value		(23)			(23)
Stock Issued During Period, Shares, New Issues									44			2
Stock Issued During Period, Value, New Issues								$ 4,221		$ 4,221	$ 1,608		$ 1,608
Foreign currency translation adjustments		2
Other Comprehensive Income (Loss), Net of Tax	[1]	2				2
Common stock dividends/distributions		(1,513)					(1,513)
Preferred stock dividends		(58)					(58)
Net income (loss)		366					366
Balance, value at Dec. 31, 2017		11,925	$ 0	$ 4	16,844		(4,919)
Balance, (in shares) at Dec. 31, 2017				406
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Convertible Preferred Stock, shares outstanding			2
Accumulated other Comprehensive Income (Loss), Net of Tax						(4)
Foreign currency translation adjustments		0
Other Comprehensive Income (Loss), Net of Tax		0
Net income (loss)	[2]	100
Balance, value at Mar. 31, 2018		12,404
Balance, value at Dec. 31, 2017		11,925	$ 0	$ 4	16,844		(4,919)
Balance, (in shares) at Dec. 31, 2017				406
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustments		(1)
Other Comprehensive Income (Loss), Net of Tax		(1)
Net income (loss)		270
Balance, value at Jun. 30, 2018		12,129
Balance, value at Dec. 31, 2017		11,925	0	$ 4	16,844		(4,919)
Balance, (in shares) at Dec. 31, 2017				406
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustments		(1)
Other Comprehensive Income (Loss), Net of Tax		(1)
Net income (loss)		421
Balance, value at Sep. 30, 2018		11,846
Balance, value at Dec. 31, 2017		11,925	0	$ 4	16,844		(4,919)
Balance, (in shares) at Dec. 31, 2017				406
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation related activity, net of forfeitures, value		116			116
Stock-based compensation related activity, net of forfeitures, shares				1
Purchases and retirement of capital stock, value		(34)			(34)
Stock Issued During Period, Shares, New Issues				8
Stock Issued During Period, Value, New Issues		841			841
Foreign currency translation adjustments		(1)
Other Comprehensive Income (Loss), Net of Tax	[1]	(1)				(1)
Common stock dividends/distributions		(1,785)					(1,785)
Preferred stock dividends		(113)					(113)
Net income (loss)		622					622
Balance, value at Dec. 31, 2018		$ 11,571	0	$ 4	17,767		(6,195)
Balance, (in shares) at Dec. 31, 2018		415		415
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accumulated other Comprehensive Income (Loss), Net of Tax		$ (4)
Balance, value at Mar. 31, 2018		12,404
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustments		(1)
Other Comprehensive Income (Loss), Net of Tax		(1)
Net income (loss)	[2]	170
Balance, value at Jun. 30, 2018		12,129
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accumulated other Comprehensive Income (Loss), Net of Tax		(5)
Foreign currency translation adjustments		0
Other Comprehensive Income (Loss), Net of Tax		0
Net income (loss)	[2]	151
Balance, value at Sep. 30, 2018		11,846
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accumulated other Comprehensive Income (Loss), Net of Tax		(5)
Foreign currency translation adjustments		0
Other Comprehensive Income (Loss), Net of Tax		0
Preferred stock dividends		28
Net income (loss)	[2]	201
Balance, value at Dec. 31, 2018		$ 11,571	$ 0	$ 4	17,767		(6,195)
Balance, (in shares) at Dec. 31, 2018		415		415
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Convertible Preferred Stock, shares outstanding		2	2
Accumulated other Comprehensive Income (Loss), Net of Tax		$ (5)				(5)
Foreign currency translation adjustments		0
Other Comprehensive Income (Loss), Net of Tax		0
Common stock dividends/distributions	[3]	471
Preferred stock dividends		28
Net income (loss)	[2]	193
Balance, value at Mar. 31, 2019		11,267
Balance, value at Dec. 31, 2018		$ 11,571	$ 0	$ 4	17,767		(6,195)
Balance, (in shares) at Dec. 31, 2018		415		415
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustments		$ 0
Other Comprehensive Income (Loss), Net of Tax		0
Net income (loss)		409
Balance, value at Jun. 30, 2019		11,013
Balance, value at Dec. 31, 2018		$ 11,571	0	$ 4	17,767		(6,195)
Balance, (in shares) at Dec. 31, 2018		415		415
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustments		$ 0
Other Comprehensive Income (Loss), Net of Tax		0
Net income (loss)		652
Balance, value at Sep. 30, 2019		10,786
Balance, value at Dec. 31, 2018		$ 11,571	0	$ 4	17,767		(6,195)
Balance, (in shares) at Dec. 31, 2018		415		415
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation related activity, net of forfeitures, value		$ 132			132
Stock-based compensation related activity, net of forfeitures, shares				1
Purchases and retirement of capital stock, value		(44)			(44)
Foreign currency translation adjustments		0
Other Comprehensive Income (Loss), Net of Tax		0
Common stock dividends/distributions		(1,917)					(1,917)
Preferred stock dividends		(113)					(113)
Net income (loss)		860					860
Balance, value at Dec. 31, 2019		$ 10,489	0	$ 4	17,855		(7,365)
Balance, (in shares) at Dec. 31, 2019		416		416
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accumulated other Comprehensive Income (Loss), Net of Tax		$ (5)
Balance, value at Mar. 31, 2019		11,267
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustments		0
Other Comprehensive Income (Loss), Net of Tax		0
Common stock dividends/distributions	[3]	471
Preferred stock dividends		28
Net income (loss)	[2]	216
Balance, value at Jun. 30, 2019		11,013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accumulated other Comprehensive Income (Loss), Net of Tax		(5)
Foreign currency translation adjustments		0
Other Comprehensive Income (Loss), Net of Tax		0
Common stock dividends/distributions	[3]	472
Preferred stock dividends		28
Net income (loss)	[2]	242
Balance, value at Sep. 30, 2019		10,786
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accumulated other Comprehensive Income (Loss), Net of Tax		(5)
Common stock dividends/distributions	[3]	502
Preferred stock dividends		28
Balance, value at Dec. 31, 2019		$ 10,489	$ 0	$ 4	$ 17,855		$ (7,365)
Balance, (in shares) at Dec. 31, 2019		416		416
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Convertible Preferred Stock, shares outstanding		2	2
Accumulated other Comprehensive Income (Loss), Net of Tax		$ (5)				$ (5)

[1] See the consolidated statement of operations and comprehensive income (loss) for the components of "total other comprehensive income (loss)."

[2] The sum of quarterly information may not agree to year-to-date information due to rounding.

[3] Inclusive of dividends accrued for holders of unvested RSUs, which will be paid when and if the RSUs vest