ALLOWANCE FOR CREDIT LOSSES - Allowance for Credit Losses Roll Forward by Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Allowance for credit losses
Allowance for credit losses on loans (ACLL) at beginning of period	$ 17,169	$ 15,393	$ 16,974	$ 16,455
Charge-offs	(1,879)	(1,212)	(3,513)	(2,452)
Recoveries	375	362	707	730
Replenishment of NCLs	1,504	850	2,806	1,722
Net reserve builds (releases)	290	520	687	(260)
Net specific reserve builds (releases)	(33)	14	5	182
Other	70	25	182	(425)
ACLL at end of period	17,496	15,952	17,496	15,952
ACLL
Collectively evaluated	17,162		17,162		$ 16,053
Individually evaluated	334		334		919
Total ACLL	17,496	15,952	17,496	15,952	16,974
Loans, net of unearned income
Collectively evaluated	653,432		653,432		647,704
Individually evaluated	1,300		1,300		4,043
Loans held at fair value	5,766		5,766		5,360
Loans, net of unearned income	660,612		660,612		657,221
Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses
Allowance for credit losses on loans (ACLL) at beginning of period	0	0	(352)	0
ACLL
Total ACLL					(352)
Cumulative Effect, Period of Adoption, Adjusted Balance
Allowance for credit losses
Allowance for credit losses on loans (ACLL) at beginning of period	17,169	15,393	16,622	16,455
ACLL
Total ACLL					16,622
Purchased credit deteriorated
ACLL
Purchased credit deteriorated	0		0		2
Loans, net of unearned income
Purchased credit deteriorated	114		114		114
Corporate
Allowance for credit losses
Allowance for credit losses on loans (ACLL) at beginning of period	2,780	3,025	2,855	2,415
Charge-offs	(86)	(57)	(125)	(105)
Recoveries	11	34	28	51
Replenishment of NCLs	75	23	97	54
Net reserve builds (releases)	(119)	(128)	(209)	249
Net specific reserve builds (releases)	(33)	49	(28)	273
Other	2	23	12	32
ACLL at end of period	2,630	2,969	2,630	2,969
ACLL
Collectively evaluated	2,335		2,335		2,532
Individually evaluated	295		295		323
Total ACLL	2,630	2,969	2,630	2,969	2,855
Loans, net of unearned income
Collectively evaluated	279,231		279,231		282,909
Individually evaluated	1,261		1,261		1,122
Loans held at fair value	5,529		5,529		5,123
Loans, net of unearned income	286,021		286,021		289,154
Corporate | Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses
Allowance for credit losses on loans (ACLL) at beginning of period			0	0
ACLL
Total ACLL					0
Corporate | Cumulative Effect, Period of Adoption, Adjusted Balance
Allowance for credit losses
Allowance for credit losses on loans (ACLL) at beginning of period			2,855	2,415
ACLL
Total ACLL					2,855
Corporate | Purchased credit deteriorated
ACLL
Purchased credit deteriorated	0		0		0
Loans, net of unearned income
Purchased credit deteriorated	0		0		0
Consumer
Allowance for credit losses
Allowance for credit losses on loans (ACLL) at beginning of period	14,389	12,368	14,119	14,040
Charge-offs	(1,793)	(1,155)	(3,388)	(2,347)
Recoveries	364	328	679	679
Replenishment of NCLs	1,429	827	2,709	1,668
Net reserve builds (releases)	409	648	896	(509)
Net specific reserve builds (releases)	0	(35)	33	(91)
Other	68	2	170	(457)
ACLL at end of period	14,866	12,983	14,866	12,983
ACLL
Collectively evaluated	14,827		14,827		13,521
Individually evaluated	39		39		596
Total ACLL	14,866	$ 12,983	14,866	12,983	14,119
Loans, net of unearned income
Collectively evaluated	374,201		374,201		364,795
Individually evaluated	39		39		2,921
Loans held at fair value	237		237		237
Loans, net of unearned income	374,591		374,591		368,067
Consumer | Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses
Allowance for credit losses on loans (ACLL) at beginning of period			(352)	0
ACLL
Total ACLL					(352)
Consumer | Cumulative Effect, Period of Adoption, Adjusted Balance
Allowance for credit losses
Allowance for credit losses on loans (ACLL) at beginning of period			13,767	$ 14,040
ACLL
Total ACLL					13,767
Consumer | Purchased credit deteriorated
ACLL
Purchased credit deteriorated	0		0		2
Loans, net of unearned income
Purchased credit deteriorated	$ 114		$ 114		$ 114