INVESTMENT SECURITIES - Gross Unrealized Losses and Fair Values of Securities (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Fair Value
Less than 12 months	$ 4,419	$ 4,990
12 months or more	8,962	2,547
Total	13,381	7,537
Gross Unrealized Losses
Less than 12 months	(270)	(94)
12 months or more	(1,431)	(67)
Total	(1,701)	(161)
U.S. Treasury and agency obligations
Fair Value
Less than 12 months	512	201
12 months or more	397	355
Total	909	556
Gross Unrealized Losses
Less than 12 months	(5)	(3)
12 months or more	(50)	(7)
Total	(55)	(10)
Mortgage-backed securities
Fair Value
Less than 12 months	1,231	2,082
12 months or more	1,683	556
Total	2,914	2,638
Gross Unrealized Losses
Less than 12 months	(104)	(49)
12 months or more	(367)	(20)
Total	(471)	(69)
Tax-exempt municipal securities
Fair Value
Less than 12 months	64	68
12 months or more	615	34
Total	679	102
Gross Unrealized Losses
Less than 12 months	(2)	(1)
12 months or more	(36)	(1)
Total	(38)	(2)
Residential
Fair Value
Less than 12 months	124	358
12 months or more	274	8
Total	398	366
Gross Unrealized Losses
Less than 12 months	(16)	(6)
12 months or more	(60)	0
Total	(76)	(6)
Commercial
Fair Value
Less than 12 months	243	295
12 months or more	1,157	400
Total	1,400	695
Gross Unrealized Losses
Less than 12 months	(13)	(4)
12 months or more	(142)	(7)
Total	(155)	(11)
Asset-backed securities
Fair Value
Less than 12 months	620	530
12 months or more	1,011	425
Total	1,631	955
Gross Unrealized Losses
Less than 12 months	(32)	(3)
12 months or more	(46)	(1)
Total	(78)	(4)
Corporate debt securities
Fair Value
Less than 12 months	1,625	1,456
12 months or more	3,825	769
Total	5,450	2,225
Gross Unrealized Losses
Less than 12 months	(98)	(28)
12 months or more	(730)	(31)
Total	$ (828)	$ (59)