Derivatives and Hedging Activities Derivatives in Statement of Income and Impact on Interest Income/Expense (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Interest income on advances		$ 854,599	$ 867,215	$ 514,176
Interest income on available-for-sale securities		115,942	143,952	118,270
Interest expense on consolidated obligations bonds		(598,585)	(545,228)	(421,622)
Advances [Member] | Interest Rate Contract [Member] | Interest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives		(72,488)
Hedge items		73,530
Net changes in fair value before price alignment interest		1,042
Price alignment interest	[1]	1,316
Net interest settlements on derivatives	[2],[3]	39,085
Net gains (losses) on qualifying fair-value hedging relationships		41,443
Amortization/accretion of discontinued fair-value hedging relationships		(1,934)
Net gain (losses) on derivatives and hedging activities recorded in net interest income		39,509
Advances [Member] | Interest Rate Contract [Member] | Interest Income [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives			447	52,055
Hedge items			257	(52,633)
Net changes in fair value			704	(578)
Net interest settlements on derivatives	[2],[3]		51,522	(24,663)
Net gains (losses) on qualifying fair-value hedging relationships			52,226	(25,241)
Amortization/accretion of discontinued fair-value hedging relationships			(1,475)	(2,176)
Less: net changes In fair value	[4]		(704)	578
Net gain (losses) on derivatives and hedging activities recorded in net interest income			50,047	(26,839)
Available-for-sale Securities [Member] | Interest Rate Contract [Member] | Interest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives		(24,274)
Hedge items		21,329
Net changes in fair value before price alignment interest		(2,945)
Price alignment interest	[1]	3,769
Net interest settlements on derivatives	[2],[3]	(22,249)
Net gains (losses) on qualifying fair-value hedging relationships		(21,425)
Amortization/accretion of discontinued fair-value hedging relationships		0
Net gain (losses) on derivatives and hedging activities recorded in net interest income		(21,425)
Available-for-sale Securities [Member] | Interest Rate Contract [Member] | Interest Income [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives			43,771	20,747
Hedge items			(42,022)	(19,011)
Net changes in fair value			1,749	1,736
Net interest settlements on derivatives	[2],[3]		(26,040)	(32,053)
Net gains (losses) on qualifying fair-value hedging relationships			(24,291)	(30,317)
Amortization/accretion of discontinued fair-value hedging relationships			0	0
Less: net changes In fair value	[4]		(1,749)	(1,736)
Net gain (losses) on derivatives and hedging activities recorded in net interest income			(26,040)	(32,053)
COs - bonds [Member] | Interest Rate Contract [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives		55,777
Hedge items		(56,091)
Net changes in fair value before price alignment interest		(314)
Price alignment interest	[1]	(786)
Net interest settlements on derivatives	[2],[3]	(17,482)
Net gains (losses) on qualifying fair-value hedging relationships		(18,582)
Amortization/accretion of discontinued fair-value hedging relationships		(2,567)
Net gain (losses) on derivatives and hedging activities recorded in net interest income		$ (21,149)
COs - bonds [Member] | Interest Rate Contract [Member] | Interest Expense [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives			(5,680)	4,611
Hedge items			5,254	(8,077)
Net changes in fair value			(426)	(3,466)
Net interest settlements on derivatives	[2],[3]		(27,895)	6,694
Net gains (losses) on qualifying fair-value hedging relationships			(28,321)	3,228
Amortization/accretion of discontinued fair-value hedging relationships			945	1,903
Less: net changes In fair value	[4]		426	3,466
Net gain (losses) on derivatives and hedging activities recorded in net interest income			$ (26,950)	$ 8,597

[1] Relates to derivatives for which variation margin payments are characterized as daily settled contracts.

[2] Excludes the interest income/expense of the respective hedged items recorded in net interest income.

[3] Represents interest income/expense on derivatives in qualifying fair-value hedging relationships. Net interest settlements on derivatives that are not in qualifying fair-value hedging relationships are reported in other income.

[4] In 2018 and 2017, net changes in fair value were recorded in net gains on derivatives and hedging activities in other income.