ALLOWANCE FOR CREDIT LOSSES - Allowance for Credit Losses Roll Forward by Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Allowance for credit losses
Allowance for credit losses on loans (ACLL) at beginning of period	$ 15,393	$ 21,638	$ 16,455	$ 24,956
Charge-offs	(1,212)	(1,844)	(2,452)	(4,052)
Recoveries	362	524	730	984
Replenishment of NCLs	850	1,320	1,722	3,068
Net reserve builds (releases)	520	(2,184)	(260)	(5,252)
Net specific reserve builds (releases)	14	(262)	182	(421)
Other	25	46	(425)	(45)
ACLL at end of period	15,952	19,238	15,952	19,238
ACLL
Collectively evaluated	14,840		14,840		$ 15,430
Individually evaluated	1,110		1,110		1,025
Total ACLL	15,952	19,238	15,952	19,238	16,455
Loans, net of unearned income
Collectively evaluated	648,228		648,228		656,265
Individually evaluated	4,462		4,462		5,301
Loans held at fair value	4,536		4,536		6,082
Total loans, net of unearned income	657,333		657,333		667,767
Purchased credit deteriorated
ACLL
Purchased credit deteriorated	2		2		0
Loans, net of unearned income
Purchased credit deteriorated	107		107		119
Corporate
Allowance for credit losses
Allowance for credit losses on loans (ACLL) at beginning of period	3,025	3,542	2,415	4,776
Charge-offs	(57)	(137)	(105)	(336)
Recoveries	34	60	51	74
Replenishment of NCLs	23	77	54	262
Net reserve builds (releases)	(128)	(751)	249	(1,944)
Net specific reserve builds (releases)	49	(112)	273	(146)
Other	23	(7)	32	(14)
ACLL at end of period	2,969	2,672	2,969	2,672
ACLL
Collectively evaluated	2,409		2,409		2,203
Individually evaluated	560		560		212
Total ACLL	2,969	2,672	2,969	2,672	2,415
Loans, net of unearned income
Collectively evaluated	295,545		295,545		283,610
Individually evaluated	1,655		1,655		1,553
Loans held at fair value	4,528		4,528		6,070
Total loans, net of unearned income	301,728		301,728		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	12,368	18,096	14,040	20,180
Charge-offs	(1,155)	(1,707)	(2,347)	(3,716)
Recoveries	328	464	679	910
Replenishment of NCLs	827	1,243	1,668	2,806
Net reserve builds (releases)	648	(1,433)	(509)	(3,308)
Net specific reserve builds (releases)	(35)	(150)	(91)	(275)
Other	2	53	(457)	(31)
ACLL at end of period	12,983	16,566	12,983	16,566
ACLL
Collectively evaluated	12,431		12,431		13,227
Individually evaluated	550		550		813
Total ACLL	12,983	$ 16,566	12,983	$ 16,566	14,040
Loans, net of unearned income
Collectively evaluated	352,683		352,683		372,655
Individually evaluated	2,807		2,807		3,748
Loans held at fair value	8		8		12
Total loans, net of unearned income	355,605		355,605		376,534
Consumer | Purchased credit deteriorated
ACLL
Purchased credit deteriorated	2		2		0
Loans, net of unearned income
Purchased credit deteriorated	$ 107		$ 107		$ 119