Investments in Securities Trading 1 (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	$ 106,744	$ 48,123
Mortgage-related securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	10,634	8,543
Fannie Mae [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	7,053	3,424
Other agency [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	3,122	4,490
Private-label and other mortgage securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	459	629
Non-mortgage-related securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	96,110	39,580
U.S. Treasury securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	96,037	39,501
Other securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	73	79
Variable Interest Entity, Primary Beneficiary [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	$ 829	$ 896