Equity - Schedule of Stock by Class (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Dividends, Preferred Stock, Cash	$ 95	$ 36	$ 0
Class A
Class of Stock [Line Items]
Common stock outstanding (in shares)	191.5	143.2	162.4	142.4
Stock Issued During Period, Shares, New Issues	36.0	0.7	0.6
Stock Issued During Period, Shares, Restricted Stock Award, Forfeited	(0.1)	(0.1)	0.0
Stock Repurchased During Period, Shares	(13.3)	(19.8)	(2.6)
Stock Issued During Period, Shares, Conversion of Convertible Securities	(25.4)	0.0	(22.0)
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture	0.3	0.0	0.0
Class B
Class of Stock [Line Items]
Common stock outstanding (in shares)	0.0	25.4	25.4	47.4
Class B | Common stock
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	(25.4)	0.0	(22.0)
Class M-1
Class of Stock [Line Items]
Common stock outstanding (in shares)	0.0	3.3	3.4	3.4
Class M-1 | Warrant
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	(3.1)	0.0	0.0
Class M-1 | Common stock
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	(0.2)	(0.1)	0.0
Class M-2
Class of Stock [Line Items]
Common stock outstanding (in shares)	0.0	0.8	0.8	0.9
Class M-2 | Warrant
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	(0.8)	0.0	0.0
Class M-2 | Common stock
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	0.0	0.0	(0.1)
Class M-3
Class of Stock [Line Items]
Common stock outstanding (in shares)	0.0	1.0	1.0	1.1
Class M-3 | Warrant
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	(1.0)	0.0	0.0
Class M-3 | Common stock
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	0.0	0.0	(0.1)
Class M-4
Class of Stock [Line Items]
Common stock outstanding (in shares)	0.0	4.0	4.1	4.7
Stock Repurchased During Period, Shares	(0.3)	0.0	(0.1)
Class M-4 | Warrant
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	(3.6)	0.0	0.0
Class M-4 | Common stock
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	0.1	0.1	0.5
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Liquidation Preference Per Share	$ 25,000
Preferred Stock, Issuance Date	Jun. 10, 2019
Dividends, Preferred Stock, Cash	$ 55	$ 31	$ 0
Series B Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Liquidation Preference Per Share	$ 25,000
Preferred Stock, Issuance Date	Sep. 19, 2019
Dividends, Preferred Stock, Cash	$ 19	5	0
Series C Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Liquidation Preference Per Share	$ 25,000
Preferred Stock, Issuance Date	Jun. 11, 2020
Dividends, Preferred Stock, Cash	$ 21	0	0
Series D Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Liquidation Preference Per Share	$ 25,000
Preferred Stock, Issuance Date	Dec. 18, 2020
Dividends, Preferred Stock, Cash	$ 0	$ 0	$ 0