CONSOLIDATED STATEMENTS OF EQUITY AND REDEEMABLE NONCONTROLLING INTERESTS - USD ($) $ in Millions	Total	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interests	Class A Common Stock	Class A Common Stock Common Stock	Class B Common Stock	Class B Common Stock Common Stock
Increase (Decrease) in Temporary Equity
Net income	$ 0
BALANCE (shares) at Dec. 31, 2018							68,897,723		25,670,684
BALANCE at Dec. 31, 2018	1,600	$ 1,121	$ 517	$ (1)	$ (38)		$ 1		$ 0
Increase (Decrease) in Stockholders' Equity
Dividends declared and paid on Class A and Class B Common Stock	(18)		(18)
Class B Common Stock converted into Class A Common Stock (in shares)							143,002		(143,002)
Class B Common Stock converted into Class A Common Stock	0
Repurchases of Class A Common Stock (in shares)							(3,493,194)
Repurchases of Class A Common Stock	(105)	(105)
Class A Common Stock issued pursuant to employee benefit plans (shares)							694,321
Class A Common Stock issued pursuant to employee benefit plans	22	22
Distributions to noncontrolling interests, net	(3)				(3)
Net (loss) income	23		22		1
BALANCE (shares) at Mar. 31, 2019							66,241,852		25,527,682
BALANCE at Mar. 31, 2019	1,519	1,038	521	(1)	(40)		$ 1		$ 0
BALANCE at Dec. 31, 2019	1,078
Increase (Decrease) in Temporary Equity
Distributions to noncontrolling interests, net	0
Distributions to redeemable noncontrolling interests	(378)
Redemption of redeemable noncontrolling interests	198
Net income	20
BALANCE at Mar. 31, 2020	522
BALANCE (shares) at Dec. 31, 2019						68,897,723	66,830,110	25,670,684	24,727,682
BALANCE at Dec. 31, 2019	1,694	1,011	492	(2)	192		$ 1		$ 0
Increase (Decrease) in Stockholders' Equity
Dividends declared and paid on Class A and Class B Common Stock	(19)		(19)
Repurchases of Class A Common Stock (in shares)							(9,957,297)
Repurchases of Class A Common Stock	(176)	(176)
Class A Common Stock issued pursuant to employee benefit plans (shares)							1,479,684
Class A Common Stock issued pursuant to employee benefit plans	29	29
Distributions to noncontrolling interests, net	(3)				(3)
Distributions to redeemable noncontrolling interests	0
Redemption of redeemable noncontrolling interests	0
Net (loss) income	131		123		8
BALANCE (shares) at Mar. 31, 2020						58,352,497	58,352,497	24,727,682	24,727,682
BALANCE at Mar. 31, 2020	$ 1,656	$ 864	$ 596	$ (2)	$ 197		$ 1		$ 0