Investment Debt Securities (Aging of Unrealized Temporary Losses) (Details) - Available-for-sale debt securities - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Available-for-sale debt securities
Less than 12 Months, Fair Value	$ 4,957	$ 3,218
Less than 12 Months, Gross Unrealized (Losses)	(21)	(21)
12 Months or More, Fair Value	6,933	6,122
12 Months or More, Gross Unrealized (Losses)	(184)	(198)
Total, Fair Value	11,890	9,340
Total, Gross Unrealized (Losses)	(205)	(219)
U.S. Government & other government related
Available-for-sale debt securities
Less than 12 Months, Fair Value	377	625
Less than 12 Months, Gross Unrealized (Losses)	(1)	(12)
12 Months or More, Fair Value	1,261	1,291
12 Months or More, Gross Unrealized (Losses)	(84)	(117)
Total, Fair Value	1,638	1,916
Total, Gross Unrealized (Losses)	(85)	(129)
State or local housing agency
Available-for-sale debt securities
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Gross Unrealized (Losses)	0	0
12 Months or More, Fair Value	5	5
12 Months or More, Gross Unrealized (Losses)	0	0
Total, Fair Value	5	5
Total, Gross Unrealized (Losses)	0	0
ABS \| FFELP
Available-for-sale debt securities
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Gross Unrealized (Losses)	0	0
12 Months or More, Fair Value	249	258
12 Months or More, Gross Unrealized (Losses)	(3)	(2)
Total, Fair Value	249	258
Total, Gross Unrealized (Losses)	(3)	(2)
GSE MBS
Available-for-sale debt securities
Less than 12 Months, Fair Value	4,308	2,544
Less than 12 Months, Gross Unrealized (Losses)	(19)	(9)
12 Months or More, Fair Value	5,415	4,565
12 Months or More, Gross Unrealized (Losses)	(97)	(79)
Total, Fair Value	9,723	7,109
Total, Gross Unrealized (Losses)	(116)	(88)
Government guaranteed MBS
Available-for-sale debt securities
Less than 12 Months, Fair Value	272	49
Less than 12 Months, Gross Unrealized (Losses)	(1)	0
12 Months or More, Fair Value	3	3
12 Months or More, Gross Unrealized (Losses)	0	0
Total, Fair Value	275	52
Total, Gross Unrealized (Losses)	$ (1)	$ 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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