Investment Securities - Available-For-Sale Securities in a Gross Unrealized Loss Position (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Less than 12 Months Fair Value	$ 93	$ 481
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(6)
12 Months or Greater Fair Value	2,005	2,229
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(65)	(108)
Agency
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Less than 12 Months Fair Value	73	448
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(6)
12 Months or Greater Fair Value	1,973	2,198
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(49)	(95)
Other mortgage-related securities [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Less than 12 Months Fair Value	20	33
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
12 Months or Greater Fair Value	32	31
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (16)	$ (13)

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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