ALLOWANCE FOR CREDIT LOSSES - Allowance for Credit Losses Roll Forward (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Allowance for credit losses
Allowance for credit losses on loans (ACLL) at beginning of period	$ 16,455	$ 24,956
Gross credit losses on loans	(1,240)	(2,208)
Gross recoveries on loans	368	460
Net credit losses on loans (NCLs)	(872)	(1,748)
Net reserve builds (releases) for loans	(781)	(3,068)
Net specific reserve builds (releases) for loans	169	(159)
Total provision for credit losses on loans (PCLL)	260	(1,479)
Other, net (see table below)	(450)	(91)
ACLL at end of period	15,393	21,638
Allowance for credit losses on unfunded commitments
Allowance for credit losses on unfunded commitments (ACLUC) at beginning of period	1,871	2,655
Provision (release) for credit losses on unfunded lending commitments	474	(626)
Other, net	(2)	(17)
ACLUC at end of period	2,343	2,012
Total allowance for credit losses on loans, leases and unfunded lending commitments	17,736	23,650
Sales or transfers of various consumer loan portfolios to HFS
Reclasses of consumer ACLL to HFS	(350)	0
FX translation and other	(100)	(91)
Other, net	$ (450)	$ (91)