Securities - Gross Unrealized Losses and Related Fair Values (Detail) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale gross unrealized losses one year or less	$ (1)	$ (45)
Securities available-for-sale aggregate fair value of investment one year or less	1,720	6,462
Securities available-for-sale gross unrealized losses greater than one year	(1,676)	(2,253)
Securities available-for-sale aggregate fair value of investment greater than one year	13,409	14,384
U.S. Treasury
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale gross unrealized losses one year or less	0	(15)
Securities available-for-sale aggregate fair value of investment one year or less	0	3,402
Securities available-for-sale gross unrealized losses greater than one year	(107)	(190)
Securities available-for-sale aggregate fair value of investment greater than one year	3,419	4,055
U.S. Government sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale gross unrealized losses one year or less	0	0
Securities available-for-sale aggregate fair value of investment one year or less	0	0
Securities available-for-sale gross unrealized losses greater than one year	(808)	(1,008)
Securities available-for-sale aggregate fair value of investment greater than one year	3,592	3,871
U.S. Government agency issued or guaranteed
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale gross unrealized losses one year or less	0	(28)
Securities available-for-sale aggregate fair value of investment one year or less	50	526
Securities available-for-sale gross unrealized losses greater than one year	(752)	(1,043)
Securities available-for-sale aggregate fair value of investment greater than one year	6,313	6,311
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale gross unrealized losses one year or less	0	0
Securities available-for-sale aggregate fair value of investment one year or less	129	0
Securities available-for-sale gross unrealized losses greater than one year	(9)	(12)
Securities available-for-sale aggregate fair value of investment greater than one year	85	97
Foreign debt securities
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale gross unrealized losses one year or less	(1)	(2)
Securities available-for-sale aggregate fair value of investment one year or less	1,541	2,534
Securities available-for-sale gross unrealized losses greater than one year	0	0
Securities available-for-sale aggregate fair value of investment greater than one year	$ 0	$ 50

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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