Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net cash provided by (used in) operating activities
Net cash provided by (used in) operating activities	$ (1,409)	$ 2,619
Cash flows provided by investing activities:
Proceeds from maturities and paydowns of trading securities held for investment	110	579
Proceeds from sales of trading securities held for investment	0	66
Proceeds from maturities and paydowns of available-for-sale securities	266	594
Proceeds from sales of available-for-sale securities	648	151
Purchases of loans held for investment	(40,045)	(41,206)
Advances to lenders	(27,898)	(28,703)
Proceeds from disposition of acquired property and preforeclosure sales	2,360	3,454
Net change in federal funds sold and securities purchased under agreements to resell or similar arrangements	(20,231)	(4,845)
Other, net	(264)	(330)
Net cash provided by investing activities	15,816	33,893
Cash flows used in financing activities:
Payments of cash dividends on senior preferred stock to Treasury	0	(5,471)
Proceeds From Senior Preferred Stock Agreement With Us Treasury	3,687	0
Other, net	442	185
Net cash used in financing activities	(37,307)	(46,380)
Net increase (decrease) in cash and cash equivalents	(22,900)	(9,868)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents at beginning of period	60,260	62,177
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents at end of period	37,360	52,309
Cash paid during the period for:
Interest	27,041	25,954
Income taxes	0	0
Fannie Mae [Member]
Cash flows provided by investing activities:
Proceeds from repayments of loans acquired as held for investment	4,164	6,718
Proceeds from sales of loans acquired as held for investment of Fannie Mae	80	0
Cash flows used in financing activities:
Proceeds from issuance of debt	288,281	230,272
Payments to redeem debt	(299,797)	(230,601)
Consolidated Trusts [Member]
Cash flows provided by investing activities:
Proceeds from repayments of loans acquired as held for investment	96,626	97,415
Cash flows used in financing activities:
Proceeds from issuance of debt	89,493	78,443
Payments to redeem debt	$ (119,413)	$ (119,208)