Selected Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest income:
Trading securities	$ 350	$ 418	$ 432	$ 427	$ 419	$ 363	$ 318	$ 236	$ 1,627	$ 1,336	$ 706
Available-for-sale securities	37	40	45	53	55	54	50	71	175	230	335
Mortgage loans interest income	28,759	28,858	29,379	29,768	29,541	28,723	28,307	28,034	116,764	114,605	108,319
Interest Income, Federal Funds Sold and Securities Purchased under Agreements to Resell	145	178	257	263	285	166	149	142	843	742	373
Other	43	47	41	32	34	38	33	31	163	136	123
Total interest income	29,334	29,541	30,154	30,543	30,334	29,344	28,857	28,514	119,572	117,049	109,856
Interest expense:
Short-term debt interest expense	(132)	(125)	(119)	(125)	(137)	(114)	(110)	(107)	(501)	(468)	(250)
Long-term debt interest expense	(23,352)	(24,187)	(24,885)	(25,685)	(25,224)	(23,861)	(23,370)	(23,175)	(98,109)	(95,630)	(88,873)
Total interest expense	(23,484)	(24,312)	(25,004)	(25,810)	(25,361)	(23,975)	(23,480)	(23,282)	(98,610)	(96,098)	(89,123)
Net interest income	5,850	5,229	5,150	4,733	4,973	5,369	5,377	5,232	20,962	20,951	20,733
Benefit (provision) for credit losses	279	1,857	1,225	650	1,080	716	1,296	217	4,011	3,309	2,041
Net interest income after benefit for credit losses	6,129	7,086	6,375	5,383	6,053	6,085	6,673	5,449	24,973	24,260	22,774
Investment gains (losses), net	923	253	461	133	259	166	277	250	1,770	952	1,522
Fair value gains (losses), net	84	(713)	(754)	(831)	(539)	386	229	1,045	(2,214)	1,121	(1,211)
Fee and other income	301	402	246	227	149	271	239	320	1,176	979	2,227
Non-interest income	1,308	(58)	(47)	(471)	(131)	823	745	1,615	732	3,052	2,538
Salaries and employee benefits	(363)	(361)	(376)	(386)	(350)	(355)	(365)	(381)	(1,486)	(1,451)	(1,328)
Professional services	(268)	(241)	(233)	(225)	(288)	(247)	(254)	(243)	(967)	(1,032)	(933)
Other administrative expenses	(155)	(147)	(135)	(133)	(176)	(138)	(136)	(126)	(570)	(576)	(476)
Total administrative expenses	(786)	(749)	(744)	(744)	(814)	(740)	(755)	(750)	(3,023)	(3,059)	(2,737)
Foreclosed property expense	(151)	(96)	(128)	(140)	(157)	(159)	(139)	(162)	(515)	(617)	(521)
Temporary Payroll Cut Continuation Act of 2011 (TCCA) fees	(626)	(613)	(600)	(593)	(586)	(576)	(565)	(557)	(2,432)	(2,284)	(2,096)
Other expenses, net	(644)	(571)	(535)	(408)	(307)	(377)	(366)	(203)	(2,158)	(1,253)	(1,511)
Total expenses	(2,207)	(2,029)	(2,007)	(1,885)	(1,864)	(1,852)	(1,825)	(1,672)	(8,128)	(7,213)	(6,865)
Income before federal income taxes	5,230	4,999	4,321	3,027	4,058	5,056	5,593	5,392	17,577	20,099	18,447
Provision for federal income taxes	(865)	(1,036)	(889)	(627)	(828)	(1,045)	(1,136)	(1,131)	(3,417)	(4,140)	(15,984)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	4,365	3,963	3,432	2,400	3,230	4,011	4,457	4,261	14,160	15,959	2,463
Dividends distributed or available for distribution to senior preferred stockholder	(4,266)	(3,977)	(3,365)	(2,361)	(3,241)	(3,975)	(4,459)	(938)	(13,969)	(12,613)	(8,944)
Net income (loss) attributable to common stockholders	$ 99	$ (14)	$ 67	$ 39	$ (11)	$ 36	$ (2)	$ 3,323	$ 191	$ 3,346	$ (6,481)
Earnings (loss) per share: Basic	$ 0.02	$ 0.00	$ 0.01	$ 0.01	$ 0.00	$ 0.01	$ 0.00	$ 0.58	$ 0.03	$ 0.58	$ (1.12)
Earnings (loss) per share: Diluted	$ 0.02	$ 0.00	$ 0.01	$ 0.01	$ 0.00	$ 0.01	$ 0.00	$ 0.56	$ 0.03	$ 0.57	$ (1.12)
Weighted-average common shares outstanding: Basic	5,762	5,762	5,762	5,762	5,762	5,762	5,762	5,762	5,762	5,762	5,762
Weighted-average common shares outstanding: Diluted	5,893	5,762	5,893	5,893	5,762	5,893	5,762	5,893	5,893	5,893	5,762