Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017
Net cash provided by (used in) operating activities
Net cash provided by (used in) operating activities	$ (1,675.0)	$ (3,626.0)
Cash flows provided by investing activities:
Proceeds from maturities and paydowns of trading securities held for investment	141.0	937.0
Proceeds from sales of trading securities held for investment	96.0	124.0
Proceeds from maturities and paydowns of available-for-sale securities	417.0	1,214.0
Proceeds from sales of available-for-sale securities	672.0	922.0
Purchases of loans held for investment	(86,615.0)	(90,180.0)
Advances to lenders	(55,151.0)	(57,533.0)
Proceeds from disposition of acquired property and preforeclosure sales	4,848.0	6,874.0
Net change in federal funds sold and securities purchased under agreements to resell or similar arrangements	3,170.0	1,195.0
Other, net	(495.0)	(208.0)
Net cash provided by investing activities	80,506.0	87,117.0
Cash flows used in financing activities:
Payments of cash dividends on senior preferred stock to Treasury	(938.0)	(8,250.0)
Proceeds from senior preferred stock purchase agreement with Treasury	3,687.0	0.0
Other, net	(20.0)	11.0
Net cash used in financing activities	(90,362.0)	(97,765.0)
Net decrease in cash, cash equivalents and restricted cash	(11,531.0)	(14,274.0)
Cash, cash equivalents and restricted cash at beginning of period	60,260.0	62,177.0
Cash, cash equivalents and restricted cash at end of period	48,729.0	47,903.0
Cash paid during the period for:
Interest	54,408.0	56,207.0
Income taxes	460.0	1,070.0
Fannie Mae [Member]
Cash flows provided by investing activities:
Proceeds from repayments of loans acquired as held for investment	7,945.0	12,835.0
Proceeds from sales of loans acquired as held for investment of Fannie Mae	2,555.0	2,361.0
Cash flows used in financing activities:
Proceeds from issuance of debt	473,373.0	489,301.0
Payments to redeem debt	(499,674.0)	(510,340.0)
Consolidated Trusts [Member]
Cash flows provided by investing activities:
Proceeds from repayments of loans acquired as held for investment	202,923.0	208,576.0
Cash flows used in financing activities:
Proceeds from issuance of debt	172,507.0	181,764.0
Payments to redeem debt	$ (239,297.0)	$ (250,251.0)

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The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income.

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The cash outflow associated with purchasing loans held for investment purposes during the period.

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