ALLOWANCE FOR CREDIT LOSSES - Allowance for Credit Losses Roll Forward by Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Allowance for credit losses
Allowance for credit losses on loans (ACLL) at beginning of period	$ 15,952	$ 19,238	$ 16,455	$ 24,956
Charge-offs	(1,237)	(1,389)	(3,689)	(5,441)
Recoveries	350	428	1,080	1,412
Replenishment of NCLs	887	961	2,609	4,029
Net reserve builds (releases)	519	(1,010)	259	(6,262)
Net specific reserve builds (releases)	(78)	(139)	104	(560)
Other	(84)	(374)	(509)	(419)
ACLL at end of period	16,309	17,715	16,309	17,715
ACLL
Collectively evaluated	15,306		15,306		$ 15,430
Individually evaluated	1,001		1,001		1,025
Total ACLL	16,309	17,715	16,309	17,715	16,455
Loans, net of unearned income
Collectively evaluated	637,668		637,668		656,265
Individually evaluated	4,303		4,303		5,301
Loans held at fair value	3,879		3,879		6,082
Total loans, net of unearned income	645,960		645,960		667,767
Purchased credit deteriorated
ACLL
Purchased credit deteriorated	2		2		0
Loans, net of unearned income
Purchased credit deteriorated	110		110		119
Corporate
Allowance for credit losses
Allowance for credit losses on loans (ACLL) at beginning of period	2,969	2,672	2,415	4,776
Charge-offs	(43)	(47)	(148)	(383)
Recoveries	37	8	88	82
Replenishment of NCLs	6	39	60	301
Net reserve builds (releases)	145	(26)	394	(1,970)
Net specific reserve builds (releases)	(104)	(21)	169	(167)
Other	(62)	(15)	(30)	(29)
ACLL at end of period	2,948	2,610	2,948	2,610
ACLL
Collectively evaluated	2,522		2,522		2,203
Individually evaluated	426		426		212
Total ACLL	2,948	2,610	2,948	2,610	2,415
Loans, net of unearned income
Collectively evaluated	283,254		283,254		283,610
Individually evaluated	1,485		1,485		1,553
Loans held at fair value	3,638		3,638		6,070
Total loans, net of unearned income	288,377		288,377		291,233
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	12,983	16,566	14,040	20,180
Charge-offs	(1,194)	(1,342)	(3,541)	(5,058)
Recoveries	313	420	992	1,330
Replenishment of NCLs	881	922	2,549	3,728
Net reserve builds (releases)	374	(984)	(135)	(4,292)
Net specific reserve builds (releases)	26	(118)	(65)	(393)
Other	(22)	(359)	(479)	(390)
ACLL at end of period	13,361	15,105	13,361	15,105
ACLL
Collectively evaluated	12,784		12,784		13,227
Individually evaluated	575		575		813
Total ACLL	13,361	$ 15,105	13,361	$ 15,105	14,040
Loans, net of unearned income
Collectively evaluated	354,414		354,414		372,655
Individually evaluated	2,818		2,818		3,748
Loans held at fair value	241		241		12
Total loans, net of unearned income	357,583		357,583		376,534
Consumer | Purchased credit deteriorated
ACLL
Purchased credit deteriorated	2		2		0
Loans, net of unearned income
Purchased credit deteriorated	$ 110		$ 110		$ 119