Fair Value (Fair Value Option) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Fair Value, Option, Quantitative Disclosures [Line Items]
Balance, beginning of the period			$ 5,441
Net gain/(loss) on advances and consolidated obligation bonds held under fair value option	$ (20)	$ (3)	(62)	$ 34
Balance, end of the period	1,879		1,879
Advances
Fair Value, Option, Quantitative Disclosures [Line Items]
Net gain/(loss) on advances and consolidated obligation bonds held under fair value option	(19)	0	(59)	43
Consolidated obligation bonds
Fair Value, Option, Quantitative Disclosures [Line Items]
Net gain/(loss) on advances and consolidated obligation bonds held under fair value option	$ (1)	$ (3)	$ (3)	$ (9)

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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