Segment Reporting - Schedule of Segment Reporting (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting Information [Line Items]
Net interest income	$ 7,184	$ 7,275	$ 21,340	$ 21,566
Fee and other income	123	66	293	206
Net revenues	7,307	7,341	21,633	21,772
(Provision) benefit for credit losses	(338)	27	(1,308)	507
Fair value gains (losses), net	13	52	347	979
Investment gains (losses), net	(1)	12	(9)	(28)
Non-interest expense:
Administrative expenses	(819)	(884)	(2,658)	(2,672)
Legislative assessments	(943)	(948)	(2,813)	(2,817)
Credit enhancement expense	(409)	(411)	(1,288)	(1,235)
Change in expected credit enhancement recoveries	46	89	96	189
Other income (expense), net	(21)	(225)	(427)	(605)
Total non-interest expense	(2,146)	(2,379)	(7,090)	(7,140)
Income before federal income taxes	4,835	5,053	13,573	16,090
Provision for federal income taxes	(976)	(1,009)	(2,736)	(3,242)
Net income	3,859	4,044	10,837	12,848
Related Party | US Treasury
Non-interest expense:
Legislative assessments	(943)	(948)
US Treasury
Non-interest expense:
Legislative assessments			(2,813)	(2,817)
Business segments | Single-Family
Segment Reporting Information [Line Items]
Net interest income	5,992	6,131	17,850	18,101
Fee and other income	104	48	238	154
Net revenues	6,096	6,179	18,088	18,255
(Provision) benefit for credit losses	(269)	451	(1,030)	1,334
Fair value gains (losses), net	(22)	(8)	257	930
Investment gains (losses), net	5	9	(1)	(48)
Non-interest expense:
Administrative expenses	(669)	(732)	(2,168)	(2,225)
Credit enhancement expense	(330)	(336)	(1,055)	(1,022)
Change in expected credit enhancement recoveries	(11)	(45)	(23)	(134)
Other income (expense), net	4	(178)	(301)	(510)
Total non-interest expense	(1,935)	(2,227)	(6,314)	(6,676)
Income before federal income taxes	3,875	4,404	11,000	13,795
Provision for federal income taxes	(790)	(890)	(2,261)	(2,819)
Net income	3,085	3,514	8,739	10,976
Business segments | Single-Family | Related Party | US Treasury
Non-interest expense:
Legislative assessments	(929)	(936)
Business segments | Single-Family | US Treasury
Non-interest expense:
Legislative assessments			(2,767)	(2,785)
Business segments | Multifamily
Segment Reporting Information [Line Items]
Net interest income	1,192	1,144	3,490	3,465
Fee and other income	19	18	55	52
Net revenues	1,211	1,162	3,545	3,517
(Provision) benefit for credit losses	(69)	(424)	(278)	(827)
Fair value gains (losses), net	35	60	90	49
Investment gains (losses), net	(6)	3	(8)	20
Non-interest expense:
Administrative expenses	(150)	(152)	(490)	(447)
Credit enhancement expense	(79)	(75)	(233)	(213)
Change in expected credit enhancement recoveries	57	134	119	323
Other income (expense), net	(25)	(47)	(126)	(95)
Total non-interest expense	(211)	(152)	(776)	(464)
Income before federal income taxes	960	649	2,573	2,295
Provision for federal income taxes	(186)	(119)	(475)	(423)
Net income	774	530	2,098	1,872
Business segments | Multifamily | Related Party | US Treasury
Non-interest expense:
Legislative assessments	$ (14)	$ (12)
Business segments | Multifamily | US Treasury
Non-interest expense:
Legislative assessments			$ (46)	$ (32)