SECURITIES - Schedule of Investments in Continuous Loss Positions (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Fair Value
Less than 12 Months	$ 10,537	$ 17,574
12 Months or Longer	13,499	5,634
Total	24,036	23,208
Gross Unrealized Losses
Less than 12 Months	(524)	(1,363)
12 Months or Longer	(1,837)	(1,099)
Total	(2,361)	(2,462)
Mortgage-backed securities
Fair Value
Less than 12 Months	7,552	13,433
12 Months or Longer	12,018	5,213
Total	19,570	18,646
Gross Unrealized Losses
Less than 12 Months	(351)	(1,144)
12 Months or Longer	(1,797)	(1,083)
Total	(2,148)	(2,227)
U.S. Treasury and other
Fair Value
Less than 12 Months	2,983	3,356
12 Months or Longer	253	0
Total	3,236	3,356
Gross Unrealized Losses
Less than 12 Months	(173)	(193)
12 Months or Longer	(20)	0
Total	(193)	(193)
Federal agencies and U.S. government sponsored entities
Fair Value
Less than 12 Months	7,552	13,353
12 Months or Longer	11,771	5,042
Total	19,323	18,395
Gross Unrealized Losses
Less than 12 Months	(351)	(1,136)
12 Months or Longer	(1,765)	(1,062)
Total	(2,116)	(2,198)
Other/non-agency
Fair Value
Less than 12 Months	0	80
12 Months or Longer	247	171
Total	247	251
Gross Unrealized Losses
Less than 12 Months	0	(8)
12 Months or Longer	(32)	(21)
Total	(32)	(29)
Collateralized loan obligations
Fair Value
Less than 12 Months	0	785
12 Months or Longer	1,228	421
Total	1,228	1,206
Gross Unrealized Losses
Less than 12 Months	0	(26)
12 Months or Longer	(20)	(16)
Total	(20)	$ (42)
State and political subdivisions
Fair Value
Less than 12 Months	2
12 Months or Longer	0
Total	2
Gross Unrealized Losses
Less than 12 Months	0
12 Months or Longer	0
Total	$ 0