Investment Securities - Gross Unrealized Losses (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Estimated Fair Value
Less than 12 months	$ 1,515	$ 0
12 months or more	25	26
Gross Unrealized Losses
Less than 12 months	(7)	0
12 months or more	(7)	(7)
State and municipal obligations
Estimated Fair Value
Less than 12 months	0	0
12 months or more	25	26
Gross Unrealized Losses
Less than 12 months	0	0
12 months or more	(7)	(7)
U.S. Government treasury obligations
Estimated Fair Value
Less than 12 months	1,515	0
12 months or more	0	0
Gross Unrealized Losses
Less than 12 months	(7)	0
12 months or more	$ 0	$ 0

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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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