Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Assets:
Restricted Cash and Cash Equivalents (includes $80,899 and $68,308, respectively, related to consolidated trusts)	$ 87,803	$ 77,286
Federal funds sold and securities purchased under agreements to resell or similar arrangements (includes $40,837 and $0, respectively, related to consolidated trusts)	54,937	28,200
Investments in securities:
Trading, at fair value (includes $6,658 and $6,544, respectively, pledged as collateral)	6,658	6,544
Available-for-sale, at fair value (with an amortized cost of $1,440 and $1,606, net of allowance of credit losses of $3)	1,440	1,606
Allowance for credit losses	3
Mortgage loans:
Mortgage loans held for investment, at fair value	6,048	6,490
Interest Receivable	9,993	9,937
Liabilities:
Interest Payable (includes $8,768 and $8,955, respectively, related to consolidated trusts)	9,585	9,719
Other Liabilities	$ 16,313	$ 15,035
Fannie Mae stockholders’ equity:
Senior preferred stock liquidation preference	146,758,000,000	142,192,000,000
Preferred stock, 700,000,000 shares are authorized	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 $3,336 and $3,728, respectively, of debt of Fannie Mae at fair value and $23,601 and $24,586, respectively, of debt of consolidated trusts, at fair value)	$ 3,336	$ 3,728
Consolidated Trusts [Member]
Assets:
Restricted Cash and Cash Equivalents (includes $80,899 and $68,308, respectively, related to consolidated trusts)	80,899	68,308
Federal funds sold and securities purchased under agreements to resell or similar arrangements (includes $40,837 and $0, respectively, related to consolidated trusts)	40,837	0
Mortgage loans:
Interest Receivable	9,732	9,635
Liabilities:
Interest Payable (includes $8,768 and $8,955, respectively, related to consolidated trusts)	8,768	8,955
Debt (includes $3,336 and $3,728, respectively, of debt of Fannie Mae at fair value and $23,601 and $24,586, respectively, of debt of consolidated trusts, at fair value)	23,601	24,586
Other Liabilities	$ 1,375	$ 1,523