Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
ASSETS
Restricted cash (includes $17,849 and $22,132, respectively, related to consolidated trusts)	$ 23,866	$ 28,150
Security Owned and Pledged as Collateral, Fair Value	3,061	747
Investments in securities:
Available-for-sale, at fair value	3,429	4,843
Mortgage loans:
Loans held for investment, at amortized cost of consolidated trusts (includes $12,057 and $14,075, respectively, at fair value)	8,922	10,596
Accrued interest receivable, net (includes $7,928 and $7,560, respectively, related to consolidated trusts)	8,490	8,133
Liabilities:
Accrued interest payable (includes $9,133 and $8,598, respectively, related to consolidated trusts)	10,211	9,682
Other liabilities (includes $356 and $492, respectively, related to consolidated trusts)	$ 9,947	$ 9,479
Fannie Mae stockholders’ equity (deficit):
Senior preferred stock, 1,000,000 shares issued	1,000,000	1,000,000
Senior preferred stock, 1,000,000 shares outstanding	1,000,000	1,000,000
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, no par value, no maximum authorization, 1,308,762,703 shares issued	1,308,762,703	1,308,762,703
Common stock, no par value, no maximum authorization, 1,158,087,567 and 1,158,082,750 shares outstanding, respectively	1,200,000,000	1,158,087,567
Treasury stock, at cost, 150,675,136 and 150,679,953 shares, respectively	150,675,136	150,675,136
Consolidated Trusts [Member]
ASSETS
Restricted cash (includes $17,849 and $22,132, respectively, related to consolidated trusts)	$ 17,849	$ 22,132
Mortgage loans:
Accrued interest receivable, net (includes $7,928 and $7,560, respectively, related to consolidated trusts)	7,928	7,560
Liabilities:
Accrued interest payable (includes $9,133 and $8,598, respectively, related to consolidated trusts)	9,133	8,598
Debt at fair value	23,753	30,493
Other liabilities (includes $356 and $492, respectively, related to consolidated trusts)	356	492
Fannie Mae [Member]
Liabilities:
Debt at fair value	$ 6,826	$ 8,186