Earnings (Loss) Per Share - Computations of Class A Basic and Diluted Earnings (Loss) per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share (less than in 2018)	9,000,000			9,000,000			9,000,000	1,000,000
Numerator for basic and diluted EPS:
Net earnings (loss) attributable to controlling interest	$ (51)			$ (13)			$ (88)	$ 156
Numerator for basic EPS - net income (loss) attributable to common stockholders	(51)			(13)			(88)	156
Add back convertible senior notes interest	0			0			0	11
Numerator for diluted EPS - net income (loss) attributable to common stockholders	$ (51)			$ (13)			$ (88)	$ 167
Denominator for EPS:
Class A common stock - basic (in shares)	97,600,393			97,460,492			97,595,765	97,464,012
Class A common stock - diluted (in shares)	97,600,393			97,460,492			97,595,765	105,788,848
Calculation of basic and diluted earnings (loss) per share:
Basic (in dollars per share)	$ (0.53)			$ (0.13)			$ (0.91)	$ 1.60
Diluted (in dollars per share)	(0.53)			(0.13)			(0.91)	1.58
Dividends declared per Class A common share (in dollars per share)	$ 0.422	$ 0.422	$ 0.422	$ 0.422	$ 0.422	$ 0.422	$ 1.27	$ 1.27
Restricted stock awards
Denominator for EPS:
Add dilutive effect (in shares)	0			0			0	153,444
Restricted stock units
Denominator for EPS:
Add dilutive effect (in shares)	0			0			0	652
Convertible senior notes
Denominator for EPS:
Add dilutive effect (in shares)	0			0			0	8,170,740