EQUITY - Changes in Shareholders' Equity (Details) - USD ($) shares in Thousands, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Changes in Shareholders' Equity
Balances, beginning of period	$ 2,114	$ 2,056	$ 2,054	$ 1,169	$ 1,016	$ 937	$ 2,054	$ 937
Net income	194	96	186	505	177	141
Distributions paid to noncontrolling interests	(58)	(38)	(71)	(51)	(43)	(61)
Other comprehensive income (loss)	2	2		3	5	(1)	4	7
Accretion of redeemable noncontrolling interests		(9)	(95)	(4)	(4)	(3)
Purchases (sales) of businesses and noncontrolling interests, net	242	(16)	(8)	3	3	(9)
Stock-based compensation expense and issuance of common stock	13	23	(10)	10	15	12
Balances, end of period	$ 2,507	$ 2,114	$ 2,056	$ 1,635	$ 1,169	$ 1,016	$ 2,507	$ 1,635
Common Stock
Changes in Shareholders' Equity
Balances, beginning of period (in shares)	107,830	107,688	107,189	106,867	106,687	106,070	107,189	106,070
Balances, beginning of period	$ 8	$ 8	$ 8	$ 8	$ 8	$ 7	$ 8	$ 7
Stock-based compensation expense and issuance of common stock (in shares)	119	142	499	202	180	617
Stock-based compensation expense and issuance of common stock						$ 1
Balances, end of period (in shares)	107,949	107,830	107,688	107,069	106,867	106,687	107,949	107,069
Balances, end of period	$ 8	$ 8	$ 8	$ 8	$ 8	$ 8	$ 8	$ 8
Additional Paid-In Capital
Changes in Shareholders' Equity
Balances, beginning of period	4,756	4,765	4,877	4,854	4,841	4,844	4,877	4,844
Accretion of redeemable noncontrolling interests		(9)	(95)	(4)	(4)	(3)
Purchases (sales) of businesses and noncontrolling interests, net	2	(23)	(7)	3	3	(10)
Stock-based compensation expense and issuance of common stock	13	23	(10)	9	14	10
Balances, end of period	4,771	4,756	4,765	4,862	4,854	4,841	4,771	4,862
Accumulated Other Comprehensive Loss
Changes in Shareholders' Equity
Balances, beginning of period	(231)	(233)	(233)	(277)	(282)	(281)	(233)	(281)
Other comprehensive income (loss)	2	2		3	5	(1)
Balances, end of period	(229)	(231)	(233)	(274)	(277)	(282)	(229)	(274)
Accumulated Deficit
Changes in Shareholders' Equity
Balances, beginning of period	(1,036)	(1,074)	(1,214)	(1,912)	(2,031)	(2,128)	(1,214)	(2,128)
Net income	131	38	140	449	119	97
Balances, end of period	(905)	(1,036)	(1,074)	(1,463)	(1,912)	(2,031)	(905)	(1,463)
Treasury Stock
Changes in Shareholders' Equity
Balances, beginning of period	(2,410)	(2,410)	(2,410)	(2,412)	(2,413)	(2,414)	(2,410)	(2,414)
Stock-based compensation expense and issuance of common stock	0	0		1	1	1
Balances, end of period	(2,410)	(2,410)	(2,410)	(2,411)	(2,412)	(2,413)	(2,410)	(2,411)
Noncontrolling Interests
Changes in Shareholders' Equity
Balances, beginning of period	1,027	1,000	1,026	908	893	909	1,026	909
Net income	63	58	46	56	58	44
Distributions paid to noncontrolling interests	(58)	(38)	(71)	(51)	(43)	(61)
Purchases (sales) of businesses and noncontrolling interests, net	240	7	(1)	0		1
Balances, end of period	$ 1,272	$ 1,027	$ 1,000	$ 913	$ 908	$ 893	$ 1,272	$ 913