EARNINGS PER SHARE - Calculation of EPS (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Basic EPS calculation
Net (loss) income	$ (7)	$ 127	$ (1,999)	$ 124
Less: net income attributable to noncontrolling interests	(22)	(33)	(97)	(85)
NET (LOSS) INCOME ATTRIBUTABLE TO COMMON STOCK	(29)	94	(2,096)	39
Adjustments:
Net income allocated to participating securities	0	(1)	0	(1)
Add: return from noncontrolling interest holders	138	0	138	0
Net income (loss) available to common shares	$ 109	$ 93	$ (1,958)	$ 38
Weighted-average common shares outstanding — basic (in shares)	49.5	49.1	49.4	48.9
Basic (in dollars per share)	$ 2.20	$ 1.89	$ (39.64)	$ 0.78
Diluted EPS calculation
Net (loss) income	$ (7)	$ 127	$ (1,999)	$ 124
Less: net income attributable to noncontrolling interests	(22)	(33)	(97)	(85)
NET (LOSS) INCOME ATTRIBUTABLE TO COMMON STOCK	(29)	94	(2,096)	39
Adjustments:
Net income allocated to participating securities	0	(1)	0	(1)
Add: return from noncontrolling interest holders	138	0	138	0
Net income (loss) available to common shares	$ 109	$ 93	$ (1,958)	$ 38
Weighted-average common shares outstanding — basic (in shares)	49.5	49.1	49.4	48.9
Dilutive effect of potentially dilutive securities (in shares)	0.0	0.1	0.0	0.3
Weighted-average common shares outstanding — diluted (in shares)	49.5	49.2	49.4	49.2
Diluted (in dollars per share)	$ 2.20	$ 1.89	$ (39.64)	$ 0.77
Weighted-average anti-dilutive shares	3.3	3.2	4.4	2.3