Investment Securities - Schedule of Unrealized Loss on Investments (Details) - USD ($)	Mar. 31, 2026	Dec. 31, 2025
Less than 12 months
Fair value	$ 2,058,000,000	$ 580,000,000
Unrealized loss	(23,000,000)	(3,000,000)
12 months or longer
Fair value	15,748,000,000	16,382,000,000
Unrealized loss	(2,954,000,000)	(2,925,000,000)
Credit reserves, available-for-sale	0	0
Credit reserves, held-to-maturity	0	0
U.S. Treasury and federal agencies
Less than 12 months
Fair value	267,000,000	0
Unrealized loss	(1,000,000)	0
12 months or longer
Fair value	572,000,000	609,000,000
Unrealized loss	(54,000,000)	(51,000,000)
U.S. States and political subdivisions
Less than 12 months
Fair value	47,000,000	24,000,000
Unrealized loss	(1,000,000)	0
12 months or longer
Fair value	398,000,000	429,000,000
Unrealized loss	(75,000,000)	(74,000,000)
Foreign government
Less than 12 months
Fair value	91,000,000	51,000,000
Unrealized loss	(1,000,000)	(1,000,000)
12 months or longer
Fair value	67,000,000	72,000,000
Unrealized loss	(3,000,000)	(3,000,000)
Agency mortgage-backed residential
Less than 12 months
Fair value	552,000,000	120,000,000
Unrealized loss	(7,000,000)	0
12 months or longer
Fair value	9,938,000,000	10,310,000,000
Unrealized loss	(2,101,000,000)	(2,084,000,000)
Mortgage-backed residential
Less than 12 months
Fair value	0	0
Unrealized loss	0	0
12 months or longer
Fair value	193,000,000	198,000,000
Unrealized loss	(33,000,000)	(32,000,000)
Agency mortgage-backed commercial
Less than 12 months
Fair value	678,000,000	299,000,000
Unrealized loss	(6,000,000)	(1,000,000)
12 months or longer
Fair value	3,548,000,000	3,629,000,000
Unrealized loss	(624,000,000)	(621,000,000)
Asset-backed
Less than 12 months
Fair value	0	0
Unrealized loss	0	0
12 months or longer
Fair value	2,000,000	12,000,000
Unrealized loss	0	0
Corporate debt
Less than 12 months
Fair value	423,000,000	86,000,000
Unrealized loss	(7,000,000)	(1,000,000)
12 months or longer
Fair value	1,030,000,000	1,123,000,000
Unrealized loss	$ (64,000,000)	$ (60,000,000)

Debt Securities, Available-for-Sale, Unrealized Loss Position, Long

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
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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, excluding accrued interest, of allowance for credit loss on investment in debt security measured at amortized cost (held-to-maturity).

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