INCOME TAXES - Components of Income Tax Provision (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current
Federal										$ 365	$ 834	$ 332
Non-U.S.										4,352	4,290	3,910
State										323	284	269
Total current income taxes										5,040	5,408	4,511
Deferred
Federal										(907)	(620)	24,902
Non-U.S.										10	371	(377)
State										287	198	352
Total deferred income taxes	[1]									(610)	(51)	24,877
Provision for income tax on continuing operations before non-controlling interests		$ 703	$ 1,079	$ 1,373	$ 1,275	$ 1,001	$ 1,471	$ 1,444	$ 1,441	4,430	5,357	29,388
Provision (benefit) for income taxes on discontinued operations										(27)	(18)	7
Income tax expense (benefit) reported in stockholders’ equity related to:
FX translation										(11)	(263)	188
Investment securities										648	(346)	(149)
Employee stock plans										(16)	(2)	(4)
Cash flow hedges										269	(8)	(12)
Benefit plans										(119)	(20)	13
FVO DVA										(337)	302	(250)
Excluded fair value hedges										8	(17)	0
Retained earnings										46	(305)	(295)
Income taxes before noncontrolling interests										4,891	4,680	28,886
Provision (benefit) for effect of securities transactions										373	104	272
Benefit for effect of other-than-temporary-impairment losses										$ (9)	$ (32)	$ (22)

[1] Includes the full impact of the $22.6 billion non-cash charge related to the Tax Cuts and Jobs Act (Tax Reform) in 2017. See Notes 1 and 9 to the Consolidated Financial Statements for further information.