SECURITIES - Schedule of Investments in Continuous Loss Positions (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Fair Value
Less than 12 Months	$ 18,171	$ 14,990
12 Months or Longer	6,265	1,236
Total	24,436	16,226
Gross Unrealized Losses
Less than 12 Months	(912)	(322)
12 Months or Longer	(697)	(55)
Total	(1,609)	(377)
U.S. Treasury and other
Fair Value
Less than 12 Months	154
12 Months or Longer	0
Total	154
Gross Unrealized Losses
Less than 12 Months	(4)
12 Months or Longer	0
Total	(4)
Federal agencies and U.S. government sponsored entities
Fair Value
Less than 12 Months	16,512	14,131
12 Months or Longer	6,265	1,236
Total	22,777	15,367
Gross Unrealized Losses
Less than 12 Months	(883)	(320)
12 Months or Longer	(697)	(55)
Total	(1,580)	(375)
Other/non-agency
Fair Value
Less than 12 Months	268	123
12 Months or Longer	0	0
Total	268	123
Gross Unrealized Losses
Less than 12 Months	(13)	(1)
12 Months or Longer	0	0
Total	(13)	(1)
Mortgage-backed securities
Fair Value
Less than 12 Months	16,780	14,254
12 Months or Longer	6,265	1,236
Total	23,045	15,490
Gross Unrealized Losses
Less than 12 Months	(896)	(321)
12 Months or Longer	(697)	(55)
Total	(1,593)	(376)
Collateralized Loan Obligations
Fair Value
Less than 12 Months	1,237	736
12 Months or Longer	0	0
Total	1,237	736
Gross Unrealized Losses
Less than 12 Months	(12)	(1)
12 Months or Longer	0	0
Total	$ (12)	$ (1)