EARNINGS PER SHARE (Details) - USD ($) shares in Thousands, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income (Numerator)
Net (loss) income	$ 514	$ (3,367)	$ 273	$ 151	$ 88	$ (49)	$ 43	$ 23	$ (2,429)	$ 105	$ 346
Net income attributable to the redeemable noncontrolling interests									(56)	(48)	0
Net loss (income) attributable to the noncontrolling interests									71	(10)	(5)
Numerator for basic and diluted earnings per common share available to common shareholders									$ (2,414)	$ 47	$ 341
Shares (Denominator)
Weighted average common shares outstanding (in shares)									79,924	92,015	100,913
Dilutive effect of outstanding stock settled appreciation rights and stock options (in shares)									0	1,170	805
Weighted-average common and common equivalent shares outstanding (in shares)									79,924	93,185	101,718
Antidilutive Securities Excluded from Computation
Antidilutive dilutive securities excluded from calculation of diluted earnings per share (in shares)									3,288	238	1,325