Investment Securities - Cost/Amortized, Unrealized Gains/Losses & FV on AFS Investment Securities (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	$ 1,797	$ 1,897
Unrealized Gains	3	1
Unrealized Losses	(160)	(169)
Fair Value	1,640	1,729
U.S. government and government sponsored entities
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	13	17
Unrealized Gains	0	0
Unrealized Losses	(1)	(1)
Fair Value	12	16
Obligations of states, municipalities, and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	75	74
Unrealized Gains	1	0
Unrealized Losses	(7)	(8)
Fair Value	69	66
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	42	55
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	42	55
Non-U.S. government and government sponsored entities
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	155	150
Unrealized Gains	0	0
Unrealized Losses	(8)	(8)
Fair Value	147	142
Corporate debt
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	1,174	1,251
Unrealized Gains	2	1
Unrealized Losses	(109)	(115)
Fair Value	1,067	1,137
RMBS
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	207	217
Unrealized Gains	0	0
Unrealized Losses	(25)	(25)
Fair Value	182	192
CMBS
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	37	38
Unrealized Gains	0	0
Unrealized Losses	(3)	(3)
Fair Value	34	35
CDO/ABS
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	94	95
Unrealized Gains	0	0
Unrealized Losses	(7)	(9)
Fair Value	$ 87	$ 86