Derivatives and Hedging Activities Net Gains (Losses) on Fair Value Hedging Relationships (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Derivative Instruments, Gain (Loss) [Line Items]
Available-for-sale securities	$ 310	$ 345	$ 632	$ 684
Consolidated obligations - Bonds	(941)	(1,244)	(1,855)	(2,301)
Consolidated obligations - Discount notes	(930)	(595)	(1,818)	(1,291)
Interest Rate Contract [Member] \| Interest Expense [Member] \| Consolidated Obligation Bonds [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) on Derivatives	(33)	15	(100)	64
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	49	(23)	126	(77)
Gain (Loss) on Fair Value Hedges Recognized in Net Interest Income	16	(8)	26	(13)
Interest Rate Contract [Member] \| Interest Expense [Member] \| Consolidated Obligation Discount Notes [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) on Derivatives	(15)	0	(30)	0
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	17	0	42	0
Gain (Loss) on Fair Value Hedges Recognized in Net Interest Income	2	0	12	0
Interest Rate Contract [Member] \| Interest Income [Member] \| Advances [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) on Derivatives	372	(157)	649	(498)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(335)	282	(573)	743
Gain (Loss) on Fair Value Hedges Recognized in Net Interest Income	37	125	76	245
Interest Rate Contract [Member] \| Interest Income [Member] \| Available-for-sale Securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) on Derivatives	222	(183)	341	(517)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(209)	233	(299)	617
Gain (Loss) on Fair Value Hedges Recognized in Net Interest Income	$ 13	$ 50	$ 42	$ 100

Total amount of gain (loss) derived from fair value hedges recognized in net interest income in the period.

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Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

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Amount of interest expense incurred on long-term debt classified as other, including, but not limited to, interest on long-term notes and amortization of issuance costs.

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Amount of interest income, amortization of premium and accretion of discount on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale); classified as operating.

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