CHANGES IN ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (AOCI) - Change in Each Component of AOCI (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Change in accumulated other comprehensive income (loss)
Balance, beginning of period			$ 202,672
Balance, end of period	$ 199,626	$ 202,910	199,626	$ 202,910
Discontinued Operations, Held-for-sale | Australia Consumer Banking Business
Change in accumulated other comprehensive income (loss)
Loss on sale of business, foreign currency translation adjustments, after-tax			470
Loss on sale of business, foreign currency translation adjustments			620
Net unrealized gains (losses) on debt securities
Change in accumulated other comprehensive income (loss)
Balance, beginning of period	(4,891)	1,535	(614)	3,320
Other comprehensive income before reclassifications	(1,612)	(379)	(5,895)	(1,898)
Increase (decrease) due to amounts reclassified from AOCI	111	(95)	117	(361)
Total other comprehensive income	(1,501)	(474)	(5,778)	(2,259)
Balance, end of period	(6,392)	1,061	(6,392)	1,061
Debt valuation adjustment (DVA)
Change in accumulated other comprehensive income (loss)
Balance, beginning of period	(394)	(1,461)	(1,187)	(1,419)
Other comprehensive income before reclassifications	1,968	(72)	2,761	(156)
Increase (decrease) due to amounts reclassified from AOCI	(1)	10	(1)	52
Total other comprehensive income	1,967	(62)	2,760	(104)
Balance, end of period	1,573	(1,523)	1,573	(1,523)
Cash flow hedges
Change in accumulated other comprehensive income (loss)
Balance, beginning of period	(1,440)	1,037	101	1,593
Other comprehensive income before reclassifications	(515)	28	(1,839)	(316)
Increase (decrease) due to amounts reclassified from AOCI	(151)	(201)	(368)	(413)
Total other comprehensive income	(666)	(173)	(2,207)	(729)
Balance, end of period	(2,106)	864	(2,106)	864
Benefit plans
Change in accumulated other comprehensive income (loss)
Balance, beginning of period	(5,681)	(6,150)	(5,852)	(6,864)
Other comprehensive income before reclassifications	(271)	36	21	689
Increase (decrease) due to amounts reclassified from AOCI	182	51	61	112
Total other comprehensive income	(89)	87	82	801
Balance, end of period	(5,770)	(6,063)	(5,770)	(6,063)
Foreign currency translation adjustment (CTA), net of hedges
Change in accumulated other comprehensive income (loss)
Balance, beginning of period	(31,180)	(29,915)	(31,166)	(28,641)
Other comprehensive income before reclassifications	(1,975)	523	(1,989)	(751)
Increase (decrease) due to amounts reclassified from AOCI	345	0	345	0
Total other comprehensive income	(1,630)	523	(1,644)	(751)
Balance, end of period	(32,810)	(29,392)	(32,810)	(29,392)
Excluded component of fair value hedges
Change in accumulated other comprehensive income (loss)
Balance, beginning of period	1	(57)	(47)	(47)
Other comprehensive income before reclassifications	4	(11)	50	(21)
Increase (decrease) due to amounts reclassified from AOCI	5	1	7	1
Total other comprehensive income	9	(10)	57	(20)
Balance, end of period	10	(67)	10	(67)
Accumulated other comprehensive income (loss)
Change in accumulated other comprehensive income (loss)
Balance, beginning of period	(43,585)	(35,011)	(38,765)	(32,058)
Other comprehensive income before reclassifications	(2,401)	125	(6,891)	(2,453)
Increase (decrease) due to amounts reclassified from AOCI	491	(234)	161	(609)
Total other comprehensive income	(1,910)	(109)	(6,730)	(3,062)
Balance, end of period	$ (45,495)	$ (35,120)	$ (45,495)	$ (35,120)