Segment Reporting - Schedule of Segment Reporting (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Segment Reporting [Line Items]
Net interest income	$ 7,559	$ 7,184	$ 22,250	$ 21,340
Fee and other income	92	123	246	293
Net revenues	7,651	7,307	22,496	21,633
Fair value gains (losses), net	630	13	675	347
Investment gains (losses), net	94	120	(130)	100
Other gains (losses), net	724	133	545	447
(Provision) benefit for credit losses	(1,140)	(338)	(1,902)	(1,308)
Non-interest expense:
Administrative expenses	(784)	(819)	(2,340)	(2,658)
Legislative assessments	(924)	(943)	(2,789)	(2,813)
Credit enhancement expense	(371)	(409)	(1,090)	(1,288)
Total non-interest expense	(2,123)	(2,267)	(6,374)	(7,199)
Income before federal income taxes	5,112	4,835	14,765	13,573
Provision for federal income taxes	(935)	(976)	(2,886)	(2,736)
Net income	4,177	3,859	11,879	10,837
Related Party | US Treasury
Non-interest expense:
Legislative assessments	(924)	(943)	(2,789)	(2,813)
Business segments
Non-interest expense:
Other income (expense), net	(44)	(96)	(155)	(440)
Business segments | Single-Family
Segment Reporting [Line Items]
Net interest income	6,268	5,992	18,494	17,850
Fee and other income	68	104	182	238
Net revenues	6,336	6,096	18,676	18,088
Fair value gains (losses), net	658	(22)	699	257
Investment gains (losses), net	92	127	(115)	108
Other gains (losses), net	750	105	584	365
(Provision) benefit for credit losses	(694)	(269)	(1,023)	(1,030)
Non-interest expense:
Administrative expenses	(630)	(669)	(1,881)	(2,168)
Credit enhancement expense	(289)	(330)	(847)	(1,055)
Other income (expense), net	(107)	(129)	(284)	(433)
Total non-interest expense	(1,938)	(2,057)	(5,766)	(6,423)
Income before federal income taxes	4,454	3,875	12,471	11,000
Provision for federal income taxes	(812)	(790)	(2,492)	(2,261)
Net income	3,642	3,085	9,979	8,739
Business segments | Single-Family | Related Party | US Treasury
Non-interest expense:
Legislative assessments	(912)	(929)	(2,754)	(2,767)
Business segments | Multifamily
Segment Reporting [Line Items]
Net interest income	1,291	1,192	3,756	3,490
Fee and other income	24	19	64	55
Net revenues	1,315	1,211	3,820	3,545
Fair value gains (losses), net	(28)	35	(24)	90
Investment gains (losses), net	2	(7)	(15)	(8)
Other gains (losses), net	(26)	28	(39)	82
(Provision) benefit for credit losses	(446)	(69)	(879)	(278)
Non-interest expense:
Administrative expenses	(154)	(150)	(459)	(490)
Credit enhancement expense	(82)	(79)	(243)	(233)
Other income (expense), net	63	33	129	(7)
Total non-interest expense	(185)	(210)	(608)	(776)
Income before federal income taxes	658	960	2,294	2,573
Provision for federal income taxes	(123)	(186)	(394)	(475)
Net income	535	774	1,900	2,098
Business segments | Multifamily | Related Party | US Treasury
Non-interest expense:
Legislative assessments	$ (12)	$ (14)	$ (35)	$ (46)