Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows provided by (used in) operating activities:
Net income	$ 22,176	$ 11,805	$ 14,160
Reconciliation of net income to net cash provided by (used in) operating activities:
Amortization of cost basis adjustments	(10,763)	(9,190)	(6,002)
Net impact of hedged mortgage assets and debt	(268)	0	0
Provision (benefit) for credit losses	(5,130)	678	(4,011)
Valuation gains	(1,996)	(2,618)	(1,809)
Current and deferred federal income taxes	300	3,152	1,517
Net gains related to the disposition of acquired property and preforeclosure sales, including credit enhancements	(1,780)	(924)	(917)
Net change in accrued interest receivable	(618)	(2,749)	332
Net change in servicer advances	(2,131)	932	(67)
Other, net	443	(225)	(363)
Net change in trading securities	46,983	(73,659)	(1,630)
Interest payment on discounted debt	(5)	(136)	(5,964)
Net cash provided by (used in) operating activities	47,211	(72,934)	(4,754)
Cash flows provided by investing activities:
Proceeds from maturities and paydowns of trading securities held for investment	41	47	58
Proceeds from sales of trading securities held for investment	160	110	49
Proceeds from maturities and paydowns of available-for-sale securities	269	364	469
Proceeds from sales of available-for-sale securities	582	361	537
Purchases of loans held for investment	(649,238)	(766,699)	(261,808)
Advances to lenders	(393,016)	(339,043)	(141,395)
Proceeds from disposition of acquired property and preforeclosure sales	3,536	5,991	7,425
Net change in securities purchased under agreements to resell or similar arrangements	7,457	(14,622)	19,360
Other, net	(341)	287	(80)
Net cash provided by investing activities	90,850	26,685	207,052
Cash flows provided by (used in) financing activities:
Payments of cash dividends on senior preferred stock to Treasury	0	0	(5,601)
Other, net	69	(510)	480
Net cash provided by (used in) financing activities	(145,053)	100,465	(190,314)
Net increase (decrease) in cash, cash equivalents and restricted cash and cash equivalents	(6,992)	54,216	11,984
Cash, cash equivalents and restricted cash and cash equivalents at beginning of period	115,623	61,407	49,423
Cash, cash equivalents and restricted cash and cash equivalents at end of period	108,631	115,623	61,407
Cash paid during the period for:
Interest	106,205	113,878	121,542
Income taxes	5,500	3,950	1,900
Non-cash activities:
Net mortgage loans acquired by assuming debt	398,026	369,733	273,174
Net transfers from mortgage loans of Fannie Mae to mortgage loans of consolidated trusts	663,849	709,451	248,463
Transfers from advances to lenders to loans held for investment of consolidated trusts	384,700	318,426	128,272
Net transfers from mortgage loans to acquired property	3,000	3,940	6,681
Fannie Mae
Cash flows provided by investing activities:
Proceeds from repayments of loans acquired as held for investment	11,212	10,672	12,508
Proceeds from sales of loans acquired as held for investment	17,130	8,744	17,794
Cash flows provided by (used in) financing activities:
Proceeds from the issuance of debt	317,867	580,220	789,572
Payments to redeem debt	(405,368)	(472,795)	(834,294)
Consolidated Trusts
Cash flows provided by investing activities:
Proceeds from repayments and sales of loans acquired as held for investment	1,093,058	1,120,473	552,135
Cash flows provided by (used in) financing activities:
Proceeds from the issuance of debt	1,097,497	1,091,242	435,235
Payments to redeem debt	$ (1,155,118)	$ (1,097,692)	$ (575,706)