Segment Reporting (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Net interest income	$ 5,347,000,000	$ 4,796,000,000
Fee and other income	308,000,000	134,000,000
Net revenues	5,655,000,000	4,930,000,000
Investment gains, net	(158,000,000)	133,000,000
Fair value gains (losses), net	(276,000,000)	(831,000,000)
Administrative expenses	(749,000,000)	(744,000,000)
Benefit (provision) for credit losses	(2,583,000,000)	650,000,000
Foreclosed property income (expense)	(80,000,000)	(140,000,000)
Credit-related income (expense)	(2,663,000,000)	510,000,000
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees	(637,000,000)	(593,000,000)
Credit enhancement expense	(331,000,000)	(171,000,000)
Other expenses, net	(263,000,000)	(207,000,000)
Income before federal income taxes	578,000,000	3,027,000,000
Provision for federal income taxes	(117,000,000)	(627,000,000)
Net income	461,000,000	2,400,000,000
Single-family [Member]
Segment Reporting Information [Line Items]
Credit enhancement expense	(312,000,000)	(167,000,000)
Multifamily [Member]
Segment Reporting Information [Line Items]
Credit enhancement expense	(19,000,000)	(4,000,000)
US Treasury [Member]
Segment Reporting Information [Line Items]
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees	(637,000,000)	(593,000,000)
Business Segments [Member] | Single-family [Member]
Segment Reporting Information [Line Items]
Net interest income	4,541,000,000	4,039,000,000
Fee and other income	152,000,000	106,000,000
Net revenues	4,693,000,000	4,145,000,000
Investment gains, net	(152,000,000)	94,000,000
Fair value gains (losses), net	(460,000,000)	(887,000,000)
Administrative expenses	(629,000,000)	(631,000,000)
Benefit (provision) for credit losses	(2,172,000,000)	661,000,000
Foreclosed property income (expense)	(78,000,000)	(143,000,000)
Credit-related income (expense)	(2,250,000,000)	518,000,000
Other expenses, net	(167,000,000)	(170,000,000)
Income before federal income taxes	86,000,000	2,309,000,000
Provision for federal income taxes	(18,000,000)	(484,000,000)
Net income	68,000,000	1,825,000,000
Business Segments [Member] | Single-family [Member] | US Treasury [Member]
Segment Reporting Information [Line Items]
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees	(637,000,000)	(593,000,000)
Business Segments [Member] | Multifamily [Member]
Segment Reporting Information [Line Items]
Net interest income	806,000,000	757,000,000
Fee and other income	156,000,000	28,000,000
Net revenues	962,000,000	785,000,000
Investment gains, net	(6,000,000)	39,000,000
Fair value gains (losses), net	184,000,000	56,000,000
Administrative expenses	(120,000,000)	(113,000,000)
Benefit (provision) for credit losses	(411,000,000)	(11,000,000)
Foreclosed property income (expense)	(2,000,000)	3,000,000
Credit-related income (expense)	(413,000,000)	(8,000,000)
Other expenses, net	(96,000,000)	(37,000,000)
Income before federal income taxes	492,000,000	718,000,000
Provision for federal income taxes	(99,000,000)	(143,000,000)
Net income	393,000,000	575,000,000
Business Segments [Member] | Multifamily [Member] | US Treasury [Member]
Segment Reporting Information [Line Items]
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees	$ 0	$ 0