Equity Common stock (Details) - shares shares in Millions	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Common Class M-1
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	(0.2)
Common stock outstanding (in shares)	0.0	3.3
Common Class A
Class of Stock [Line Items]
Stock Issued During Period, Shares, New Issues	35.9
Stock Issued During Period, Shares, Restricted Stock Award, Forfeited	0.1
Stock Issued During Period, Shares, Conversion of Convertible Securities	(25.4)
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	0.3
Common stock outstanding (in shares)	191.5	143.2
Stock Repurchased During Period, Shares	13.2
Common Class B
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	(25.4)
Common stock outstanding (in shares)	0.0	25.4
Common Class M-2
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	0.0
Common stock outstanding (in shares)	0.0	0.8
Common Class M-3
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	0.0
Common stock outstanding (in shares)	0.0	1.0
Common Class M-4
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	0.1
Common stock outstanding (in shares)	0.0	4.0
Stock Repurchased During Period, Shares	0.3
Warrant | Common Class M-1
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	(3.1)
Warrant | Common Class M-2
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	(0.8)
Warrant | Common Class M-3
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	(1.0)
Warrant | Common Class M-4
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities	(3.6)