CONSOLIDATED STATEMENTS OF EQUITY AND REDEEMABLE NONCONTROLLING INTERESTS - USD ($)	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	1,600,000,000	$ 1,121,000,000	$ 517,000,000	$ (1,000,000)	$ (38,000,000)		$ 1,000,000		$ 0
Increase (Decrease) in Stockholders' Equity
Dividends declared and paid on Class A and Class B Common Stock	(36,000,000)		(36,000,000)
Class B Common Stock converted into Class A Common Stock (in shares)							643,002		(643,002)
Class B Common Stock converted into Class A Common Stock	0
Repurchases of Class A Common Stock (in shares)							(3,993,194)
Repurchases of Class A Common Stock	(125,000,000)	(125,000,000)
Class A Common Stock issued pursuant to employee benefit plans (shares)							1,484,557
Class A Common Stock issued pursuant to employee benefit plans	28,000,000	28,000,000
Distributions to noncontrolling interests, net	(4,000,000)				(4,000,000)
Net (loss) income	66,000,000		64,000,000		2,000,000
BALANCE (shares) at Jun. 30, 2019							67,032,088		25,027,682
BALANCE at Jun. 30, 2019	1,529,000,000	1,024,000,000	545,000,000	(1,000,000)	(40,000,000)		$ 1,000,000		$ 0
Increase (Decrease) in Temporary Equity
Net income	0
BALANCE (shares) at Mar. 31, 2019							66,241,852		25,527,682
BALANCE at Mar. 31, 2019	1,519,000,000	1,038,000,000	521,000,000	(1,000,000)	(40,000,000)		$ 1,000,000		$ 0
Increase (Decrease) in Stockholders' Equity
Dividends declared and paid on Class A and Class B Common Stock	(18,000,000)		(18,000,000)
Class B Common Stock converted into Class A Common Stock	0						$ 500,000		$ (500,000)
Repurchases of Class A Common Stock (in shares)							(500,000)
Repurchases of Class A Common Stock	(20,000,000)	(20,000,000)
Class A Common Stock issued pursuant to employee benefit plans (shares)							790,236
Class A Common Stock issued pursuant to employee benefit plans	6,000,000	6,000,000
Distributions to noncontrolling interests, net	(1,000,000)				(1,000,000)
Net (loss) income	43,000,000		42,000,000		1,000,000
BALANCE (shares) at Jun. 30, 2019							67,032,088		25,027,682
BALANCE at Jun. 30, 2019	1,529,000,000	1,024,000,000	545,000,000	(1,000,000)	(40,000,000)		$ 1,000,000		$ 0
BALANCE at Dec. 31, 2019	1,078,000,000
Increase (Decrease) in Temporary Equity
Distributions to noncontrolling interests, net	(24,000,000)
Distributions to redeemable noncontrolling interests	(378,000,000)
Redemption of redeemable noncontrolling interests	(198,000,000)
Net income	32,000,000
BALANCE at Jun. 30, 2020	510,000,000
BALANCE (shares) at Dec. 31, 2019						68,897,723	66,830,110	25,670,684	24,727,682
BALANCE at Dec. 31, 2019	1,694,000,000	1,011,000,000	492,000,000	(2,000,000)	192,000,000		$ 1,000,000		$ 0
Increase (Decrease) in Stockholders' Equity
Dividends declared and paid on Class A and Class B Common Stock	(35,000,000)		(35,000,000)
Repurchases of Class A Common Stock (in shares)							(15,144,930)
Repurchases of Class A Common Stock	(261,000,000)	(261,000,000)
Class A Common Stock issued pursuant to employee benefit plans (shares)							1,657,156
Class A Common Stock issued pursuant to employee benefit plans	37,000,000	37,000,000
Distributions to noncontrolling interests, net	(7,000,000)				(7,000,000)
Distributions to redeemable noncontrolling interests	0
Redemption of redeemable noncontrolling interests	0
Other comprehensive loss	(9,000,000)			(9,000,000)
Net (loss) income	392,000,000		375,000,000		17,000,000
BALANCE (shares) at Jun. 30, 2020						53,342,336	53,342,336	24,727,682	24,727,682
BALANCE at Jun. 30, 2020	1,811,000,000	787,000,000	832,000,000	(11,000,000)	202,000,000		$ 1,000,000		$ 0
BALANCE at Mar. 31, 2020	522,000,000
Increase (Decrease) in Temporary Equity
Distributions to noncontrolling interests, net	(24,000,000)
Net income	12,000,000
BALANCE at Jun. 30, 2020	510,000,000
BALANCE (shares) at Mar. 31, 2020							58,352,497		24,727,682
BALANCE at Mar. 31, 2020	1,656,000,000	864,000,000	596,000,000	(2,000,000)	197,000,000		$ 1,000,000		$ 0
Increase (Decrease) in Stockholders' Equity
Dividends declared and paid on Class A and Class B Common Stock	(16,000,000)		(16,000,000)
Repurchases of Class A Common Stock (in shares)							(5,187,633)
Repurchases of Class A Common Stock	(85,000,000)	(85,000,000)
Class A Common Stock issued pursuant to employee benefit plans (shares)							177,472
Class A Common Stock issued pursuant to employee benefit plans	8,000,000	8,000,000
Distributions to noncontrolling interests, net	(4,000,000)				(4,000,000)
Other comprehensive loss	(9,000,000)			(9,000,000)
Net (loss) income	261,000,000		252,000,000		9,000,000
BALANCE (shares) at Jun. 30, 2020						53,342,336	53,342,336	24,727,682	24,727,682
BALANCE at Jun. 30, 2020	$ 1,811,000,000	$ 787,000,000	$ 832,000,000	$ (11,000,000)	$ 202,000,000		$ 1,000,000		$ 0