Derivatives and Hedging Activities (Cash Flow Hedges) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Derivative Instruments, Gain (Loss) [Line Items]
Maximum Hedging Period For Forecasted Cash Flows	15 years
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net	$ 0
Cash Flow Hedge Gain (Loss) to be Reclassified within 12 Months	0
Cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gross Amount Initially Recognized in AOCI	(9)	$ 6	$ (28)	$ 24
Amount Reclassified from AOCI into Net Interest Income	5	11	13	22
Cash flow hedges \| Discount notes
Derivative Instruments, Gain (Loss) [Line Items]
Gross Amount Initially Recognized in AOCI	(3)	5	(8)	23
Amount Reclassified from AOCI into Net Interest Income	3	10	10	21
Cash flow hedges \| Consolidated obligation bonds
Derivative Instruments, Gain (Loss) [Line Items]
Gross Amount Initially Recognized in AOCI	(6)	1	(20)	1
Amount Reclassified from AOCI into Net Interest Income	$ 2	$ 1	$ 3	$ 1

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
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-Section 50
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The amount of net gain (loss) reclassified into earnings in the period when cash flow hedge is discontinued because it is probable that the original forecasted transactions will not occur by the end of the original period or an additional two month time period.

+ References

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The amount of net gains or losses on interest rate cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income upon the hedged transaction affecting earnings.

+ References

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Maximum period of hedging exposure to variability in future cash flows for forecasted transaction of interest rate cash flow hedge, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Excludes forecasted transaction for payment of variable interest on existing financial instrument.

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Amount, before reclassification, of tax expense (benefit) for gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
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