Investments in Securities Trading 1 (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	$ 26,630	$ 30,768
Mortgage-related securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	13,547	14,462
Freddie Mac [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	1,766	1,839
Ginnie Mae [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	234	407
Alt-A private-label securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	1,194	1,516
Subprime private-label securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	1,282	1,448
CMBS [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	2,641	2,718
Mortgage revenue bonds [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	643	565
Other mortgage-related securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	101	99
U.S. Treasury securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	13,083	16,306
Fannie Mae [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	$ 5,686	$ 5,870