Mortgage Loans Narratives (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Mortgage Loans on Real Estate [Abstract]
Carrying value of loans redesignated from HFI to HFS	$ 19	$ 74	$ 2,200	$ 74
Sale of loans, unpaid principal balance	$ 862		$ 1,900
Minimum Months Past Due of Single-Family Nonaccrual Loans			2 months
Average term extension of a single-family modified loan	162 months	154 months	161 months	151 months
Average interest rate reduction of a single-family modified loan	0.99%	1.70%	1.12%	1.76%