CONSOLIDATED STATEMENTS OF EQUITY (DEFICIT) 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
Redeemable noncontrolling interest, beginning balance at Dec. 31, 2019	$ 1,078
Increase (Decrease) in Temporary Equity
Distributions to noncontrolling interests, net	(24)
Distributions to redeemable noncontrolling interests	(378)
Redemption of redeemable noncontrolling interests	(198)
Net income (loss)	32
Redeemable noncontrolling interest, ending balance at Jun. 30, 2020	510
Beginning balance (in shares) at Dec. 31, 2019							66,830,110		24,727,682
Beginning 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	(35)		(35)
Repurchases of Class A Common Stock (in shares)							(15,144,930)
Repurchases of Class A Common Stock	(261)	(261)
Class A Common Stock issued pursuant to employee benefit plans (in shares)							1,657,156
Class A Common Stock issued pursuant to employee benefit plans	37	37
Distributions to noncontrolling interests, net	(7)				(7)
Other comprehensive income (loss)	(9)			(9)
Net income (loss)	392		375		17
Ending balance (in shares) at Jun. 30, 2020							53,342,336		24,727,682
Ending balance at Jun. 30, 2020	1,811	787	832	(11)	202		$ 1		$ 0
Redeemable noncontrolling interest, beginning balance at Mar. 31, 2020	522
Increase (Decrease) in Temporary Equity
Distributions to noncontrolling interests, net	(24)
Net income (loss)	12
Redeemable noncontrolling interest, ending balance at Jun. 30, 2020	510
Beginning balance (in shares) at Mar. 31, 2020							58,352,497		24,727,682
Beginning balance at Mar. 31, 2020	1,656	864	596	(2)	197		$ 1		$ 0
Increase (Decrease) in Stockholders' Equity
Dividends declared and paid on Class A and Class B Common Stock	(16)		(16)
Repurchases of Class A Common Stock (in shares)							(5,187,633)
Repurchases of Class A Common Stock	(85)	(85)
Class A Common Stock issued pursuant to employee benefit plans (in shares)							177,472
Class A Common Stock issued pursuant to employee benefit plans	8	8
Distributions to noncontrolling interests, net	(4)				(4)
Other comprehensive income (loss)	(9)			(9)
Net income (loss)	261		252		9
Ending balance (in shares) at Jun. 30, 2020							53,342,336		24,727,682
Ending balance at Jun. 30, 2020	1,811	787	832	(11)	202		$ 1		$ 0
Redeemable noncontrolling interest, beginning balance at Dec. 31, 2020	190
Increase (Decrease) in Temporary Equity
Distributions to noncontrolling interests, net	(9)
Net income (loss)	9
Redeemable noncontrolling interest, ending balance at Jun. 30, 2021	190
Beginning balance (in shares) at Dec. 31, 2020						49,252,671	49,252,671	24,727,682	24,727,682
Beginning balance at Dec. 31, 2020	(1,185)	721	(1,986)	(10)	89		$ 1		$ 0
Increase (Decrease) in Stockholders' Equity
Dividends declared and paid on Class A and Class B Common Stock	(30)		(30)
Class B Common Stock converted into Class A Common Stock (in shares)							952,626		(952,626)
Class A Common Stock issued pursuant to employee benefit plans (in shares)							1,411,627
Class A Common Stock issued pursuant to employee benefit plans	19	19
Distributions to noncontrolling interests, net	(50)				(50)
Other comprehensive income (loss)	5			5
Net income (loss)	(311)		(344)		33
Ending balance (in shares) at Jun. 30, 2021						51,616,924	51,616,924	23,775,056	23,775,056
Ending balance at Jun. 30, 2021	(1,552)	740	(2,360)	(5)	72		$ 1		$ 0
Redeemable noncontrolling interest, beginning balance at Mar. 31, 2021	188
Increase (Decrease) in Temporary Equity
Distributions to noncontrolling interests, net	(3)
Net income (loss)	5
Redeemable noncontrolling interest, ending balance at Jun. 30, 2021	190
Beginning balance (in shares) at Mar. 31, 2021							51,118,350		24,217,682
Beginning balance at Mar. 31, 2021	(1,186)	735	(2,013)	(2)	93		$ 1		$ 0
Increase (Decrease) in Stockholders' Equity
Dividends declared and paid on Class A and Class B Common Stock	(15)		(15)
Class B Common Stock converted into Class A Common Stock (in shares)							442,626		(442,626)
Class A Common Stock issued pursuant to employee benefit plans (in shares)							55,948
Class A Common Stock issued pursuant to employee benefit plans	5	5
Distributions to noncontrolling interests, net	(20)				(20)
Other comprehensive income (loss)	(3)			(3)
Net income (loss)	(333)		(332)		(1)
Ending balance (in shares) at Jun. 30, 2021						51,616,924	51,616,924	23,775,056	23,775,056
Ending balance at Jun. 30, 2021	$ (1,552)	$ 740	$ (2,360)	$ (5)	$ 72		$ 1		$ 0