Statements of Capital Accounts - USD ($) shares in Millions, $ in Millions	Total	Total Retained Earnings	Total Restricted Retained Earnings	Unrestricted Retained Earnings	Accumulated Other Comprehensive Income/(Loss)	Common Class B - Putable Common Stock
Balance, Shares at Dec. 31, 2016						24
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of capital stock, shares						12
Repurchase of capital stock, shares						(4)
Net Shares Reclassified from/(to) Mandatorily Redeemable Capital Stock, Shares						0
Balance, Shares at Dec. 31, 2017						32
Balance at Dec. 31, 2016	$ 5,537	$ 3,056	$ 2,168	$ 888	$ 111	$ 2,370
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive Income (Loss)	583	376	178	198	207
Issuance of capital stock, value	1,214					1,214
Repurchase of capital stock, value	(339)					(339)
Capital stock reclassified from/(to) mandatorily redeemable capital stock, net, value	(2)					(2)
Retained Earnings, Appropriated, Transfers To (From)	0	0	(1,771)	1,771
Cash dividends on capital stock	(187)	(187)		(187)
Balance at Dec. 31, 2017	6,806	3,245	575	2,670	318	$ 3,243
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of capital stock, shares						14
Repurchase of capital stock, shares						(17)
Net Shares Reclassified from/(to) Mandatorily Redeemable Capital Stock, Shares						0
Balance, Shares at Dec. 31, 2018						29
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive Income (Loss)	277	360	72	288	(83)
Issuance of capital stock, value	1,377					$ 1,377
Repurchase of capital stock, value	(1,669)					(1,669)
Capital stock reclassified from/(to) mandatorily redeemable capital stock, net, value	(2)					(2)
Cash dividends on capital stock	(259)	(259)		(259)
Balance at Dec. 31, 2018	6,530	3,346	647	2,699	235	$ 2,949
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of capital stock, shares						12
Repurchase of capital stock, shares						(11)
Net Shares Reclassified from/(to) Mandatorily Redeemable Capital Stock, Shares						0
Balance, Shares at Dec. 31, 2019						30
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive Income (Loss)	366	327	66	261	39
Issuance of capital stock, value	1,186					$ 1,186
Repurchase of capital stock, value	(1,129)					(1,129)
Capital stock reclassified from/(to) mandatorily redeemable capital stock, net, value	(6)					(6)
Cash dividends on capital stock	(206)	(206)		(206)
Balance at Dec. 31, 2019	$ 6,741	$ 3,467	$ 713	$ 2,754	$ 274	$ 3,000