Fair Value (Carrying Value and Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025	Mar. 31, 2025	Dec. 31, 2024
Fair Value [Member]
Assets
Cash and due from banks	$ 58	$ 44
Interest-bearing deposits	4,553	3,726
Securities purchased under agreements to resell	16,440	17,090
Federal funds sold	4,650	5,930
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
Held-to-Maturity Securities, Fair Value	432	452
Advances	127,153	110,441
Mortgage loans held for portfolio, net	14,313	14,034
Accrued interest receivable	469	461
Derivative assets, net	7	80
Other assets	48	50
Liabilities
Deposits	(1,426)	(1,147)
Federal Home Loan Bank, Consolidated Obligations Fair Value Disclosure	(187,534)	(173,448)
Mandatorily redeemable capital stock	(72)	(30)
Accrued interest payable	(638)	(589)
Derivative liabilities, net	(69)	(3)
Reported Value Measurement [Member]
Assets
Cash and due from banks	58	44
Interest-bearing deposits	4,553	3,726
Securities purchased under agreements to resell	16,440	17,090
Federal funds sold	4,650	5,930
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
Held-to-maturity securities	429	447
Advances	127,032	110,230
Mortgage loans held for portfolio, net	14,910	14,540
Accrued interest receivable	469	461
Derivative assets, net	7	80
Other assets	48	50
Liabilities
Deposits	(1,426)	(1,147)
Federal Home Loan Bank, Consolidated Obligations Fair Value Disclosure	(188,059)	(173,869)
Mandatorily redeemable capital stock	(72)	(30)
Accrued interest payable	(638)	(589)
Derivative liabilities, net	(69)	(3)
Cash and due from banks	58	44
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	6,109	6,303
Held-to-Maturity Securities, Fair Value	432	452
Loans to Other Federal Home Loan Banks	0	0	$ 0	$ 0
Accrued interest receivable	469	461
Derivative assets, net	7	80
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
Mandatorily redeemable capital stock	(72)	(30)
Accrued interest payable	(638)	(589)
Derivative liabilities, net	(69)	(3)
Loans from Other Federal Home Loan Banks			0	0
Federal Home Loan Bank of Cincinnati
Liabilities
Loans from Other Federal Home Loan Banks			$ 0	$ 0
Fair Value, Level 1 [Member]
Assets
Cash and due from banks	58	44
Interest-bearing deposits	0	0
Securities purchased under agreements to resell	0	0
Federal funds sold	0	0
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	0	0
Debt Securities, Available-for-sale	0	0
Held-to-Maturity Securities, Fair Value	0	0
Advances	0	0
Mortgage loans held for portfolio, net	0	0
Accrued interest receivable	0	0
Derivative assets, net	0	0
Other assets	48	50
Liabilities
Deposits	0	0
Federal Home Loan Bank, Consolidated Obligations Fair Value Disclosure	0	0
Mandatorily redeemable capital stock	(72)	(30)
Accrued interest payable	0	0
Derivative liabilities, net	0	0
Fair Value, Level 2 [Member]
Assets
Cash and due from banks	0	0
Interest-bearing deposits	4,553	3,726
Securities purchased under agreements to resell	16,440	17,090
Federal funds sold	4,650	5,930
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
Held-to-Maturity Securities, Fair Value	430	450
Advances	127,153	110,441
Mortgage loans held for portfolio, net	14,271	13,996
Accrued interest receivable	469	461
Derivative assets, net	161	240
Other assets	0	0
Liabilities
Deposits	(1,426)	(1,147)
Federal Home Loan Bank, Consolidated Obligations Fair Value Disclosure	(187,534)	(173,448)
Mandatorily redeemable capital stock	0	0
Accrued interest payable	(638)	(589)
Derivative liabilities, net	(114)	(29)
Fair Value, Level 3 [Member]
Assets
Cash and due from banks	0	0
Interest-bearing deposits	0	0
Securities purchased under agreements to resell	0	0
Federal funds sold	0	0
Trading securities (includes $1,613 and $1,390 pledged as collateral that may be repledged)	0	0
Debt Securities, Available-for-sale	0	0
Held-to-Maturity Securities, Fair Value	2	2
Advances	0	0
Mortgage loans held for portfolio, net	42	38
Accrued interest receivable	0	0
Derivative assets, net	0	0
Other assets	0	0
Liabilities
Deposits	0	0
Federal Home Loan Bank, Consolidated Obligations Fair Value Disclosure	0	0
Mandatorily redeemable capital stock	0	0
Accrued interest payable	0	0
Derivative liabilities, net	0	0
Consolidated Obligation Discount Notes [Member] | Fair Value [Member]
Liabilities
Discount notes	(84,631)	(84,617)
Consolidated Obligation Discount Notes [Member] | Reported Value Measurement [Member]
Liabilities
Discount notes	(84,642)	(84,620)
Consolidated Obligation Discount Notes [Member] | Fair Value Option Election
Liabilities
Discount notes	10,239	17,382
Consolidated Obligation Discount Notes [Member] | Fair Value, Level 1 [Member]
Liabilities
Discount notes	0	0
Consolidated Obligation Discount Notes [Member] | Fair Value, Level 2 [Member]
Liabilities
Discount notes	(84,631)	(84,617)
Consolidated Obligation Discount Notes [Member] | Fair Value, Level 3 [Member]
Liabilities
Discount notes	0	0
Consolidated Obligation Bonds [Member] | Fair Value [Member]
Liabilities
Bonds, Fair Value	(102,903)	(88,831)
Consolidated Obligation Bonds [Member] | Reported Value Measurement [Member]
Liabilities
Bonds, Fair Value	(103,417)	(89,249)
Consolidated Obligation Bonds [Member] | Fair Value, Level 1 [Member]
Liabilities
Bonds, Fair Value	0	0
Consolidated Obligation Bonds [Member] | Fair Value, Level 2 [Member]
Liabilities
Bonds, Fair Value	(102,903)	(88,831)
Consolidated Obligation Bonds [Member] | Fair Value, Level 3 [Member]
Liabilities
Bonds, Fair Value	$ 0	$ 0