EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator (basic and diluted):
Net income	$ 1,045	$ 840	$ 865
Less: Preferred stock dividends	14	7	0
Net income available to common stockholders	$ 1,031	$ 833	$ 865
Denominator:
Weighted-average common shares outstanding - basic (in shares)	522,093,545	535,599,731	556,674,146
Dilutive common shares: share-based awards (in shares)	1,837,173	2,621,167	1,050,790
Weighted-average common shares outstanding - diluted (in shares)	523,930,718	538,220,898	557,724,936
Earnings per common share:
Basic (in dollars per share)	$ 1.97	$ 1.55	$ 1.55
Diluted (in dollars per share)	$ 1.97	$ 1.55	$ 1.55