Carrying Value and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands		Mar. 31, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		$ 806,985	$ 69,416
Trading securities		3,563,368	2,250,264
Available-for-sale securities Fair Value		7,246,334	7,409,000
Held-to-maturity securities	[1],[2]	676,888	871,107
Fair value of held-to-maturity securities		733,970	1,035,410
Accrued interest receivable		109,878	112,163
Derivative assets		227,720	159,731
Derivative Assets, Netting Adjustments and Cash Collateral	[3],[4]	196,861	144,402
Mandatorily redeemable capital stock		(6,112)	(5,806)
Accrued interest payable		(108,010)	(104,477)
Derivative liabilities		(24,404)	(10,271)
Derivative liability, Netting Adjustments and Cash Collateral	[3],[4]	80,245	33,534
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		806,985	69,416
Interest-bearing deposits		1,130,563	1,253,873
Securities purchased under agreements to resell		0	0
Federal funds sold		0	0
Trading securities	[5]	0	0
Available-for-sale securities Fair Value	[5]	0	0
Fair value of held-to-maturity securities		0	0
Advances		0	0
Mortgage loans, net		0	0
Accrued interest receivable		0	0
Derivative assets	[5]	0	0
Other assets	[5]	16,238	13,894
Deposits		0	0
Mandatorily redeemable capital stock		(6,112)	(5,806)
Accrued interest payable		0	0
Derivative liabilities	[5]	0	0
Level 1 [Member] | Commitments to make additional advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0	0
Level 1 [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0	0
Level 1 [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		0	0
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		0	0
Interest-bearing deposits		0	0
Securities purchased under agreements to resell		1,999,954	3,500,003
Federal funds sold		3,454,927	859,999
Trading securities	[5]	3,563,368	2,250,264
Available-for-sale securities Fair Value	[5]	7,180,939	7,344,348
Fair value of held-to-maturity securities		384,446	456,942
Advances		45,434,302	34,735,775
Mortgage loans, net		4,747,540	4,615,737
Accrued interest receivable		109,878	112,163
Derivative assets	[5]	30,859	15,329
Other assets	[5]	14,688	18,045
Deposits		(859,815)	(674,269)
Mandatorily redeemable capital stock		0	0
Accrued interest payable		(108,010)	(104,477)
Derivative liabilities	[5]	(104,649)	(43,805)
Level 2 [Member] | Commitments to make additional advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(2,623)	(3,884)
Level 2 [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(1,540)	(1,723)
Level 2 [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(39,735,774)	(27,681,470)
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
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	[5]	0	0
Available-for-sale securities Fair Value	[5]	65,395	64,652
Fair value of held-to-maturity securities		349,524	578,468
Advances		0	0
Mortgage loans, net		19,195	18,404
Accrued interest receivable		0	0
Derivative assets	[5]	0	0
Other assets	[5]	0	0
Deposits		0	0
Mandatorily redeemable capital stock		0	0
Accrued interest payable		0	0
Derivative liabilities	[5]	0	0
Level 3 [Member] | Commitments to make additional advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0	0
Level 3 [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0	0
Level 3 [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		0	0
Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		806,985	69,416
Interest-bearing deposits		1,130,563	1,253,873
Securities purchased under agreements to resell		2,000,000	3,500,000
Federal funds sold		3,455,000	860,000
Trading securities	[5]	3,563,368	2,250,264
Available-for-sale securities Fair Value	[5]	7,246,334	7,409,000
Held-to-maturity securities		676,888	871,107
Advances		45,076,223	34,595,363
Mortgage loans, net		4,528,474	4,501,251
Accrued interest receivable		109,878	112,163
Derivative assets	[5]	227,720	159,731
Other assets	[5]	30,926	31,939
Deposits		(859,816)	(674,309)
Mandatorily redeemable capital stock		(6,112)	(5,806)
Accrued interest payable		(108,010)	(104,477)
Derivative liabilities	[5]	(24,404)	(10,271)
Carrying Value [Member] | Commitments to make additional advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		0	0
Carrying Value [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(1,540)	(1,723)
Carrying Value [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(39,692,253)	(27,681,169)
Total Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks		806,985	69,416
Interest-bearing deposits		1,130,563	1,253,873
Securities purchased under agreements to resell		1,999,954	3,500,003
Federal funds sold		3,454,927	859,999
Trading securities	[5]	3,563,368	2,250,264
Available-for-sale securities Fair Value	[5]	7,246,334	7,409,000
Fair value of held-to-maturity securities		733,970	1,035,410
Advances		45,434,302	34,735,775
Mortgage loans, net		4,766,735	4,634,141
Accrued interest receivable		109,878	112,163
Derivative assets	[5]	227,720	159,731
Other assets	[5]	30,926	31,939
Deposits		(859,815)	(674,269)
Mandatorily redeemable capital stock		(6,112)	(5,806)
Accrued interest payable		(108,010)	(104,477)
Derivative liabilities	[5]	(24,404)	(10,271)
Total Fair Value [Member] | Commitments to make additional advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(2,623)	(3,884)
Total Fair Value [Member] | Standby Letters of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other		(1,540)	(1,723)
Total Fair Value [Member] | COs - Discount notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Discount notes		(39,735,774)	(27,681,470)
COs - bonds [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		0	0
COs - bonds [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		(25,122,573)	(24,226,123)
COs - bonds [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		0	0
COs - bonds [Member] | Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		(24,576,586)	(23,888,493)
COs - bonds [Member] | Total Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
CO Bonds		$ (25,122,573)	$ (24,226,123)

[1] Carrying value of held-to-maturity securities represents the sum of amortized cost and the amount of noncredit-related other-than-temporary impairment recognized in accumulated other comprehensive loss and the allowance for credit losses.

[2] Fair values of held-to-maturity securities were $733,970 and $1,035,410 at March 31, 2020, and December 31, 2019, respectively.

[3] Amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions with the same counterparty. Cash collateral and related accrued interest posted was $278.3 million and $178.5 million at March 31, 2020, and December 31, 2019, respectively. The change in cash collateral posted is included in the net change in interest-bearing deposits in the statement of cash flows. Cash collateral and related accrued interest received was $1.2 million and $561 thousand at March 31, 2020, and December 31, 2019.

[4] These amounts represent the effect of master-netting agreements intended to allow us to settle positive and negative positions and also cash collateral and related accrued interest held or placed with the same clearing member and/or counterparty.

[5] Carried at fair value and measured on a recurring basis.