Selected Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest income:
Trading securities	$ 162	$ 177	$ 219	$ 316	$ 350	$ 418	$ 432	$ 427	$ 874	$ 1,627	$ 1,336
Available-for-sale securities	22	19	26	31	37	40	45	53	98	175	230
Mortgage loans interest income	24,561	25,810	27,007	28,938	28,929	29,072	29,511	29,862	106,316	117,374	115,029
Interest Income, Federal Funds Sold and Securities Purchased under Agreements to Resell or similar arrangements	11	14	14	107	145	178	257	263	146	843	742
Other	43	33	25	34	43	47	41	32	135	163	136
Total interest income	24,799	26,053	27,291	29,426	29,504	29,755	30,286	30,637	107,569	120,182	117,473
Interest expense:
Short-term debt interest expense	(7)	(19)	(54)	(102)	(132)	(125)	(119)	(125)	(182)	(501)	(468)
Long-term debt interest expense	(17,706)	(19,378)	(21,460)	(23,977)	(23,450)	(24,282)	(24,940)	(25,716)	(82,521)	(98,388)	(95,732)
Total interest expense	(17,713)	(19,397)	(21,514)	(24,079)	(23,582)	(24,407)	(25,059)	(25,841)	(82,703)	(98,889)	(96,200)
Net interest income	7,086	6,656	5,777	5,347	5,922	5,348	5,227	4,796	24,866	21,293	21,273
Benefit (provision) for credit losses	1,416	501	(12)	(2,583)	279	1,857	1,225	650	(678)	4,011	3,309
Net interest income after benefit (provision) for credit losses	8,502	7,157	5,765	2,764	6,201	7,205	6,452	5,446	24,188	25,304	24,582
Investment gains (losses), net	263	653	149	(158)	923	253	461	133	907	1,770	952
Fair value gains (losses), net	(880)	(327)	(1,018)	(276)	84	(713)	(754)	(831)	(2,501)	(2,214)	1,121
Fee and other income	159	93	90	120	131	188	113	134	462	566	555
Non-interest income (loss)	(458)	419	(779)	(314)	1,138	(272)	(180)	(564)	(1,132)	122	2,628
Salaries and employee benefits	(393)	(386)	(382)	(393)	(363)	(361)	(376)	(386)	(1,554)	(1,486)	(1,451)
Professional services	(248)	(230)	(231)	(212)	(268)	(241)	(233)	(225)	(921)	(967)	(1,032)
Other administrative expenses	(162)	(146)	(141)	(144)	(155)	(147)	(135)	(133)	(593)	(570)	(576)
Total administrative expenses	(803)	(762)	(754)	(749)	(786)	(749)	(744)	(744)	(3,068)	(3,023)	(3,059)
Foreclosed property expense	(16)	(71)	(10)	(80)					(177)	(515)	(617)
Foreclosed property expense					(151)	(96)	(128)	(140)	(177)	(515)	(617)
Temporary Payroll Cut Continuation Act of 2011 (TCCA) fees	(697)	(679)	(660)	(637)	(626)	(613)	(600)	(593)	(2,673)	(2,432)	(2,284)
Credit Enhancement Expense	(300)	(325)	(360)	(376)	(352)	(290)	(276)	(216)	(1,361)	(1,134)	(679)
Change in expected credit enhancement recoveries	(180)	(48)	273	188					233	0	0
Other expenses, net	(339)	(313)	(261)	(218)	(194)	(186)	(203)	(162)	(1,131)	(745)	(472)
Total expenses	(2,335)	(2,198)	(1,772)	(1,872)	(2,109)	(1,934)	(1,951)	(1,855)	(8,177)	(7,849)	(7,111)
Income before federal income taxes	5,709	5,378	3,214	578	5,230	4,999	4,321	3,027	14,879	17,577	20,099
Provision for federal income taxes	(1,139)	(1,149)	(669)	(117)	(865)	(1,036)	(889)	(627)	(3,074)	(3,417)	(4,140)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	4,570	4,229	2,545	461	4,365	3,963	3,432	2,400	11,805	14,160	15,959
Dividends distributed or available for distribution to senior preferred stockholder	(4,566)	(4,216)	(2,532)	(476)	(4,266)	(3,977)	(3,365)	(2,361)	(11,790)	(13,969)	(12,613)
Net income attributable to common stockholders	$ 4	$ 13	$ 13	$ (15)	$ 99	$ (14)	$ 67	$ 39	$ 15	$ 191	$ 3,346
Earnings (loss) per share: Basic	$ 0.00	$ 0.00	$ (0.00)	$ (0.00)	$ 0.02	$ 0.00	$ 0.01	$ 0.01	$ 0.00	$ 0.03	$ 0.58
Earnings (loss) per share: Diluted	$ 0.00	$ 0.00	$ (0.00)	$ (0.00)	$ 0.02	$ 0.00	$ 0.01	$ 0.01	$ 0.00	$ 0.03	$ 0.57
Weighted-average common shares outstanding: Basic	5,867	5,867	5,867	5,867	5,762	5,762	5,762	5,762	5,867	5,762	5,762
Weighted-average common shares outstanding: Diluted	5,893	5,893	5,893	5,867	5,893	5,762	5,893	5,893	5,893	5,893	5,893