EARNINGS PER COMMON SHARE COMPUTATION (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income available for common stockholders	$ 3,367	$ 2,707	$ 1,683
Weighted-average outstanding shares of common stock used to compute basic earnings per common share (in shares)	132,199	134,055	137,486
Shares used to compute diluted earnings per common share (in shares)	133,012	134,727	138,403
Basic earnings per common share (in dollars per share)	$ 25.47	$ 20.20	$ 12.24
Diluted earnings per common share (in dollars per share)	$ 25.31	$ 20.10	$ 12.16
Number of antidilutive stock options and restricted stock awards excluded from computation (in shares)	238	478	223
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)	92	107	194
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)	721	565	723