EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator (basic and diluted):
Net income	$ 253	$ 453	$ 287	$ 892
Less: Preferred stock dividends	28	18	50	33
Net income available to common stockholders	$ 225	$ 435	$ 237	$ 859
Denominator:
Weighted-average common shares outstanding - basic (in shares)	426,613,053	458,154,335	427,165,737	459,426,685
Dilutive common shares: share-based awards (in shares)	953,867	1,149,889	1,126,843	1,430,850
Weighted-average common shares outstanding - diluted (in shares)	427,566,920	459,304,224	428,292,580	460,857,535
Earnings per common share:
Basic (in dollars per share)	$ 0.53	$ 0.95	$ 0.56	$ 1.87
Diluted (in dollars per share)	$ 0.53	$ 0.95	$ 0.55	$ 1.86
Share-based awards excluded from diluted earnings per share computation (in shares)	1,579,361	371,627	1,211,751	1,073,431