SECURITIES - Schedule of Investments in Continuous Loss Positions (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Fair Value
Less than 12 Months	$ 10,289	$ 17,574
12 Months or Longer	12,716	5,634
Total	23,005	23,208
Gross Unrealized Losses
Less than 12 Months	(421)	(1,363)
12 Months or Longer	(1,619)	(1,099)
Total	(2,040)	(2,462)
Mortgage-backed securities
Fair Value
Less than 12 Months	7,135	13,433
12 Months or Longer	11,402	5,213
Total	18,537	18,646
Gross Unrealized Losses
Less than 12 Months	(305)	(1,144)
12 Months or Longer	(1,576)	(1,083)
Total	(1,881)	(2,227)
U.S. Treasury and other
Fair Value
Less than 12 Months	3,114	3,356
12 Months or Longer	138	0
Total	3,252	3,356
Gross Unrealized Losses
Less than 12 Months	(116)	(193)
12 Months or Longer	(10)	0
Total	(126)	(193)
Federal agencies and U.S. government sponsored entities
Fair Value
Less than 12 Months	7,101	13,353
12 Months or Longer	11,185	5,042
Total	18,286	18,395
Gross Unrealized Losses
Less than 12 Months	(302)	(1,136)
12 Months or Longer	(1,550)	(1,062)
Total	(1,852)	(2,198)
Other/non-agency
Fair Value
Less than 12 Months	34	80
12 Months or Longer	217	171
Total	251	251
Gross Unrealized Losses
Less than 12 Months	(3)	(8)
12 Months or Longer	(26)	(21)
Total	(29)	(29)
Collateralized loan obligations
Fair Value
Less than 12 Months	39	785
12 Months or Longer	1,176	421
Total	1,215	1,206
Gross Unrealized Losses
Less than 12 Months	0	(26)
12 Months or Longer	(33)	(16)
Total	(33)	$ (42)
State and political subdivisions
Fair Value
Less than 12 Months	1
12 Months or Longer	0
Total	1
Gross Unrealized Losses
Less than 12 Months	0
12 Months or Longer	0
Total	$ 0