Segment Reporting - Segment Financial Results (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest income	$ 129,820	$ 117,877	$ 105,363
Interest expense	(108,417)	(98,140)	(86,821)
Net interest income	21,403	19,737	18,542
Non-interest income
Guarantee income	1,592	1,611	1,615
Investment gains (losses), net	(209)	2,076	707
Other income (loss)	485	488	365
Noninterest Income	1,868	4,175	2,687
Net revenues	23,271	23,912	21,229
(Provision) benefit for credit losses	(1,290)	(476)	872
Administrative Expense	(2,886)	(2,843)	(2,795)
Credit enhancement expense	(2,082)	(2,345)	(2,339)
Legislative and regulatory assessments	(3,323)	(3,233)	(3,131)
Other Noninterest Expense	(329)	(237)	(637)
Non-interest expense	(8,620)	(8,658)	(8,902)
Income before income tax expense	13,361	14,778	13,199
Income tax expense	(2,630)	(2,920)	(2,661)
Net income	10,731	11,858	10,538
Other comprehensive income (loss), net of taxes and reclassification adjustments	78	(5)	166
Comprehensive income (loss)	10,809	11,853	10,704
Operating segments | Single Family Guarantee Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest income	123,670	113,681	102,174
Interest expense	(103,892)	(95,168)	(84,517)
Net interest income	19,778	18,513	17,657
Non-interest income
Guarantee income	100	83	103
Investment gains (losses), net	(317)	939	296
Other income (loss)	298	284	211
Noninterest Income	81	1,306	610
Net revenues	19,859	19,819	18,267
(Provision) benefit for credit losses	(758)	(374)	1,172
Administrative Expense	(2,219)	(2,225)	(2,214)
Credit enhancement expense	(1,882)	(2,174)	(2,223)
Legislative and regulatory assessments	(3,264)	(3,178)	(3,085)
Other Noninterest Expense	(284)	(206)	(596)
Non-interest expense	(7,649)	(7,783)	(8,118)
Income before income tax expense	11,452	11,662	11,321
Income tax expense	(2,254)	(2,305)	(2,282)
Net income	9,198	9,357	9,039
Other comprehensive income (loss), net of taxes and reclassification adjustments	22	(1)	10
Comprehensive income (loss)	9,220	9,356	9,049
Operating segments | Multifamily Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest income	6,150	4,196	3,189
Interest expense	(4,525)	(2,972)	(2,304)
Net interest income	1,625	1,224	885
Non-interest income
Guarantee income	1,492	1,528	1,512
Investment gains (losses), net	108	1,137	411
Other income (loss)	187	204	154
Noninterest Income	1,787	2,869	2,077
Net revenues	3,412	4,093	2,962
(Provision) benefit for credit losses	(532)	(102)	(300)
Administrative Expense	(667)	(618)	(581)
Credit enhancement expense	(200)	(171)	(116)
Legislative and regulatory assessments	(59)	(55)	(46)
Other Noninterest Expense	(45)	(31)	(41)
Non-interest expense	(971)	(875)	(784)
Income before income tax expense	1,909	3,116	1,878
Income tax expense	(376)	(615)	(379)
Net income	1,533	2,501	1,499
Other comprehensive income (loss), net of taxes and reclassification adjustments	56	(4)	156
Comprehensive income (loss)	$ 1,589	$ 2,497	$ 1,655