Investment Securities - Schedule of Cost/Amortized, Unrealized Gains/Losses & FV on AFS Investment Securities (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	$ 1,695	$ 1,641
Unrealized Gains	10	6
Unrealized Losses	(82)	(108)
Fair Value	1,623	1,539
U.S. government and government sponsored entities
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	31	12
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	31	12
Obligations of states, municipalities, and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	60	66
Unrealized Gains	0	0
Unrealized Losses	(4)	(5)
Fair Value	56	61
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	39	9
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	39	9
Non-U.S. government and government sponsored entities
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	155	159
Unrealized Gains	1	1
Unrealized Losses	(4)	(5)
Fair Value	152	155
Corporate debt
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	1,099	1,086
Unrealized Gains	7	4
Unrealized Losses	(49)	(69)
Fair Value	1,057	1,021
RMBS
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	208	208
Unrealized Gains	1	0
Unrealized Losses	(21)	(24)
Fair Value	188	184
CMBS
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	25	29
Unrealized Gains	0	0
Unrealized Losses	(2)	(2)
Fair Value	23	27
CDO/ABS
Debt Securities, Available-for-sale [Line Items]
Cost/ Amortized Cost	78	72
Unrealized Gains	1	1
Unrealized Losses	(2)	(3)
Fair Value	$ 77	$ 70

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost excluding accrued interest, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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