Investments in Securities Trading 1 (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	$ 30,844	$ 30,768
Mortgage-related securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	13,087	14,462
Freddie Mac [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	1,500	1,839
Ginnie Mae [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	323	407
Alt-A private-label securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	1,135	1,516
Subprime private-label securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	1,316	1,448
CMBS [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	2,550	2,718
Mortgage revenue bonds [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	693	565
Other mortgage-related securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	99	99
U.S. Treasury securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	17,757	16,306
Fannie Mae [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	$ 5,471	$ 5,870