EARNINGS PER COMMON SHARE COMPUTATION (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income available for common stockholders	$ 1,828	$ 940	$ 2,301	$ 1,506
Weighted average outstanding shares of common stock used to compute basic earnings per common share (in shares)	132,248	135,063	132,192	135,223
Shares used to compute diluted earnings per common share (in shares)	133,023	135,579	132,917	135,770
Basic earnings per common share (in dollars per share)	$ 13.83	$ 6.96	$ 17.41	$ 11.14
Diluted earnings per common share (in dollars per share)	$ 13.75	$ 6.94	$ 17.31	$ 11.10
Number of antidilutive stock options and restricted stock excluded from computation (in shares)	130	761	395	732
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)	89	67	90	98
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)	686	449	635	449