EARNINGS PER COMMON SHARE COMPUTATION (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income available for common stockholders	$ 566	$ 491
Weighted average outstanding shares of common stock used to compute basic earnings per common share (in shares)	135,383	137,903
Shares used to compute diluted earnings per common share (in shares)	135,962	138,830
Basic earnings per common share (in dollars per share)	$ 4.18	$ 3.56
Diluted earnings per common share (in dollars per share)	$ 4.16	$ 3.53
Number of antidilutive stock options and restricted stock excluded from computation (in shares)	703	645
Employee stock options
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dilutive effect of employee stock options and restricted stock (in shares)	130	213
Restricted stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dilutive effect of employee stock options and restricted stock (in shares)	449	714