Derivatives and Hedging Activities (Derivatives in Statement of Income and Impact on Interest) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) on Derivative	$ 112,541	$ (50,266)	$ (286,893)	$ (287,936)
Gains/(Losses) on Hedged Item	(112,829)	47,631	282,154	279,710
Net Interest Settlements on FV Hedges	(55,038)	(659)	(96,053)	(10,758)
Gain (Loss) on Fair Value Hedges Recognized in Net Interest Income	(55,326)	(3,294)	(100,792)	(18,984)
Interest income on advances	95,201	478,477	548,953	1,508,189
Interest Income on Available-for-sale	31,996	71,884	138,565	201,198
Interest Income on MPF loans	35,932	42,452	121,561	126,922
Interest Expense on Consolidated obligation - bonds	(80,579)	(413,901)	(462,006)	(1,259,974)
Interest Income [Member] | Interest Rate Swap [Member] | Advances [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) on Derivative	124,582	(34,790)	(188,539)	(347,838)
Gains/(Losses) on Hedged Item	(124,569)	34,652	188,424	347,605
Net Interest Settlements on FV Hedges	(69,603)	8,521	(136,712)	51,693
Gain (Loss) on Fair Value Hedges Recognized in Net Interest Income	(69,590)	8,383	(136,827)	51,460
Interest Income [Member] | Interest Rate Swap [Member] | Available-for-sale Securities
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) on Derivative	9,402	(30,639)	(103,292)	(102,668)
Gains/(Losses) on Hedged Item	(8,918)	29,136	100,135	98,539
Net Interest Settlements on FV Hedges	(7,070)	2,918	(13,734)	1,534
Gain (Loss) on Fair Value Hedges Recognized in Net Interest Income	(6,586)	1,415	(16,891)	(2,595)
Interest Income [Member] | Interest Rate Swap [Member] | Mortgage Receivable [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) on Derivative	0	0	0	0
Gains/(Losses) on Hedged Item	(1,035)	(755)	(2,118)	(2,320)
Net Interest Settlements on FV Hedges	0	0	0	0
Gain (Loss) on Fair Value Hedges Recognized in Net Interest Income	(1,035)	(755)	(2,118)	(2,320)
Interest Expense [Member] | Interest Rate Swap [Member] | Consolidated Obligations Bonds [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) on Derivative	(21,443)	15,163	4,938	162,570
Gains/(Losses) on Hedged Item	21,693	(15,402)	(4,287)	(164,114)
Net Interest Settlements on FV Hedges	21,635	(12,098)	54,393	(63,985)
Gain (Loss) on Fair Value Hedges Recognized in Net Interest Income	$ 21,885	$ (12,337)	$ 55,044	$ (65,529)