Investment Securities - Gross Unrealized Losses Ratio to Fair Value (Details) $ in Millions	Jun. 30, 2025 USD ($) security	Dec. 31, 2024 USD ($) security
Number of Securities
Less than 12 months | security	0	0
12 months or more | security	9	45
Total | security	9	45
Estimated Fair Value
Less than 12 months	$ 0	$ 0
12 months or more	145	152
Total	145	152
Gross Unrealized Losses
Less than 12 months	0	0
12 months or more	(9)	(12)
Total	$ (9)	$ (12)
90–100%
Number of Securities
Less than 12 months | security	0	0
12 months or more | security	5	30
Total | security	5	30
Estimated Fair Value
Less than 12 months	$ 0	$ 0
12 months or more	128	129
Total	128	129
Gross Unrealized Losses
Less than 12 months	0	0
12 months or more	(2)	(3)
Total	$ (2)	$ (3)
Less than 90%
Number of Securities
Less than 12 months | security	0	0
12 months or more | security	4	15
Total | security	4	15
Estimated Fair Value
Less than 12 months	$ 0	$ 0
12 months or more	17	23
Total	17	23
Gross Unrealized Losses
Less than 12 months	0	0
12 months or more	(7)	(9)
Total	$ (7)	$ (9)