Fair Value (Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	$ 6,109	$ 6,303
Derivative Asset, Subject to Master Netting Arrangement, Gross Liability and Collateral, Obligation to Return Cash, Offset	(154)	(160)
Derivative assets, net	7	80
Derivative Liability, Subject to Master Netting Arrangement, Gross Asset and Collateral, Right to Reclaim Cash, Offset	45	26
Derivative liabilities, net	(69)	(3)
Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	0	0
Debt Securities, Available-for-sale	0	0
Derivative assets, net	0	0
Other assets	48	50
Derivative liabilities, net	0	0
Mortgage loans held for portfolio, net	0	0
Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	6,109	6,303
Debt Securities, Available-for-sale	27,418	27,519
Derivative assets, net	161	240
Other assets	0	0
Derivative liabilities, net	(114)	(29)
Mortgage loans held for portfolio, net	14,271	13,996
Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	0	0
Debt Securities, Available-for-sale	0	0
Derivative assets, net	0	0
Other assets	0	0
Derivative liabilities, net	0	0
Mortgage loans held for portfolio, net	42	38
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Subject to Master Netting Arrangement, Gross Liability and Collateral, Obligation to Return Cash, Offset	(154)	(160)
Derivative assets, net	7	80
Derivative Liability, Subject to Master Netting Arrangement, Gross Asset and Collateral, Right to Reclaim Cash, Offset	45	26
Fair Value, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	0	0
Debt Securities, Available-for-sale	0	0
Derivative assets, net	0	0
Other assets	48	50
Total recurring assets	48	50
Derivative liabilities, net	0	0
Total recurring liabilities	0	0
Fair Value, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	6,109	6,303
Debt Securities, Available-for-sale	27,418	27,519
Derivative assets, net	161	240
Other assets	0	0
Total recurring assets	33,688	34,062
Derivative liabilities, net	(114)	(29)
Total recurring liabilities	(10,353)	(17,411)
Fair Value, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	0	0
Debt Securities, Available-for-sale	0	0
Derivative assets, net	0	0
Other assets	0	0
Total recurring assets	0	0
Derivative liabilities, net	0	0
Total recurring liabilities	0	0
Fair Value, Nonrecurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total recurring assets	0	0
Mortgage loans held for portfolio, net	0	0
Fair Value, Nonrecurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total recurring assets	0	0
Mortgage loans held for portfolio, net	0	0
Fair Value, Nonrecurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total recurring assets	2	6
Mortgage loans held for portfolio, net	2	6
Interest Rate Swap [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Subject to Master Netting Arrangement, Gross Liability and Collateral, Obligation to Return Cash, Offset	(154)	(160)
Derivative Liability, Subject to Master Netting Arrangement, Gross Asset and Collateral, Right to Reclaim Cash, Offset	45	26
Interest Rate Swap [Member] | Fair Value, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, net	0	0
Derivative liabilities, net	0	0
Interest Rate Swap [Member] | Fair Value, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, net	159	240
Derivative liabilities, net	(112)	(29)
Interest Rate Swap [Member] | Fair Value, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, net	0	0
Derivative liabilities, net	0	0
Forward Contracts [Member] | Fair Value, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, net	0
Forward Contracts [Member] | Fair Value, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, net	2
Forward Contracts [Member] | Fair Value, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, net	0
Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	6,109	6,303
Debt Securities, Available-for-sale	27,418	27,519
Derivative assets, net	7	80
Other assets	48	50
Derivative liabilities, net	(69)	(3)
Mortgage loans held for portfolio, net	14,313	14,034
Fair Value [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	6,109	6,303
Debt Securities, Available-for-sale	27,418	27,519
Other assets	48	50
Total recurring assets	33,582	33,952
Derivative liabilities, net	(69)	(3)
Total recurring liabilities	(10,308)	(17,385)
Fair Value [Member] | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total recurring assets	2	6
Mortgage loans held for portfolio, net	2	6
Fair Value [Member] | Interest Rate Swap [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, net	5	80
Derivative liabilities, net	(67)	(3)
Fair Value [Member] | Forward Contracts [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, net	2
Consolidated Obligation Discount Notes [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount notes	0	0
Consolidated Obligation Discount Notes [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount notes	84,631	84,617
Consolidated Obligation Discount Notes [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount notes	0	0
Consolidated Obligation Discount Notes [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount notes	10,200	17,400
Consolidated Obligation Discount Notes [Member] | Fair Value, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount notes	0	0
Consolidated Obligation Discount Notes [Member] | Fair Value, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount notes	10,239	17,382
Consolidated Obligation Discount Notes [Member] | Fair Value, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount notes	0	0
Consolidated Obligation Discount Notes [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount notes	84,631	84,617
US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	5,914	6,104
US Treasury Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	0	0
US Treasury Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	5,914	6,104
US Treasury Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	0	0
US Treasury Securities [Member] | Fair Value [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	5,914	6,104
U.S. obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	54	57
U.S. obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	0	0
Debt Securities, Available-for-sale	0	0
U.S. obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	54	57
Debt Securities, Available-for-sale	6	14
U.S. obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	0	0
Debt Securities, Available-for-sale	0	0
U.S. obligations [Member] | Fair Value [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	54	57
Debt Securities, Available-for-sale	6	14
GSE obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	47	48
GSE obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	0	0
Debt Securities, Available-for-sale	0	0
GSE obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	47	48
Debt Securities, Available-for-sale	307	310
GSE obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	0	0
Debt Securities, Available-for-sale	0	0
GSE obligations [Member] | Fair Value [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	47	48
Debt Securities, Available-for-sale	307	310
State or local housing agency obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0	0
State or local housing agency obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	415	370
State or local housing agency obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0	0
State or local housing agency obligations [Member] | Fair Value [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	415	370
Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	94	94
Other [Member] | Fair Value, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	0	0
Debt Securities, Available-for-sale	0	0
Other [Member] | Fair Value, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	94	94
Debt Securities, Available-for-sale	19	19
Other [Member] | Fair Value, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	0	0
Debt Securities, Available-for-sale	0	0
Other [Member] | Fair Value [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	94	94
Debt Securities, Available-for-sale	19	19
U.S. obligations MBS [Member] | Single Family [Member] | Fair Value, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0	0
U.S. obligations MBS [Member] | Single Family [Member] | Fair Value, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	5,885	5,707
U.S. obligations MBS [Member] | Single Family [Member] | Fair Value, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0	0
U.S. obligations MBS [Member] | Single Family [Member] | Fair Value [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	5,885	5,707
Mortgage-backed securities, GSE [Member] | Single Family [Member] | Fair Value, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0	0
Mortgage-backed securities, GSE [Member] | Single Family [Member] | Fair Value, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	208	217
Mortgage-backed securities, GSE [Member] | Single Family [Member] | Fair Value, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0	0
Mortgage-backed securities, GSE [Member] | Single Family [Member] | Fair Value [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	208	217
Mortgage-backed securities, GSE [Member] | Multifamily [Member] | Fair Value, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0	0
Mortgage-backed securities, GSE [Member] | Multifamily [Member] | Fair Value, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	20,578	20,882
Mortgage-backed securities, GSE [Member] | Multifamily [Member] | Fair Value, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0	0
Mortgage-backed securities, GSE [Member] | Multifamily [Member] | Fair Value [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	20,578	20,882
Mortgages [Member] | Forward Contracts [Member] | Fair Value, Recurring [Member] | Fair Value, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities, net	0
Mortgages [Member] | Forward Contracts [Member] | Fair Value, Recurring [Member] | Fair Value, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities, net	(2)
Mortgages [Member] | Forward Contracts [Member] | Fair Value, Recurring [Member] | Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities, net	0
Mortgages [Member] | Fair Value [Member] | Forward Contracts [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities, net	(2)
Fair Value Option Election | Consolidated Obligation Discount Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount notes	(10,239)	(17,382)
Fair Value Option Election | Consolidated Obligation Discount Notes [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount notes	$ (10,239)	$ (17,382)