Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Assets:
Restricted Cash and Cash Equivalents	$ 73,516	$ 40,223
Investments in securities:
Investments in securities, pledged as collateral	6,237	3,037
Amortized cost of investments in securities	1,780	2,281
Allowance for credit losses	3
Mortgage loans:
Mortgage loans held for investment, at fair value	6,968	7,825
Interest Receivable	9,748	8,604
Liabilities:
Interest Payable	9,982	10,228
Other Liabilities	$ 14,124	$ 11,097
Fannie Mae stockholders’ equity:
Senior preferred stock liquidation preference	137,976,000,000	131,178,000,000
Preferred stock, 700,000,000 shares are authorized	700,000,000	700,000,000
Preferred stock, 555,374,922 shares issued	555,374,922	555,374,922
Preferred stock, 555,374,922 shares outstanding	555,374,922	555,374,922
Common stock, 1,308,762,703 shares issued	1,308,762,703	1,308,762,703
Common stock, 1,158,087,567 shares outstanding	1,158,087,567	1,158,087,567
Treasury stock, at cost, 150,675,136 shares	150,675,136	150,675,136
Fannie Mae [Member]
Liabilities:
Debt (includes $3,986 and $5,687, respectively, of debt of Fannie Mae at fair value and $24,741 and $21,880, respectively, of debt of consolidated trusts, at fair value)	$ 3,986	$ 5,687
Consolidated Trusts [Member]
Assets:
Restricted Cash and Cash Equivalents	65,431	33,294
Mortgage loans:
Interest Receivable	9,867	8,172
Liabilities:
Interest Payable	9,133	9,361
Debt (includes $3,986 and $5,687, respectively, of debt of Fannie Mae at fair value and $24,741 and $21,880, respectively, of debt of consolidated trusts, at fair value)	24,741	21,880
Other Liabilities	$ 1,813	$ 376