Allowance for Loan Losses and Total Recorded Investment in HFI Loans (Details) - USD ($) $ in Millions	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	$ 26,517		$ 31,375
Allowance for loan losses for collectively reserved loans	2,618		4,166
Total allowance for loan losses	29,135	$ 31,150	35,541	$ 36,931	$ 39,067	$ 43,846
Recorded investment in individually impaired loans	176,638		188,186
Recorded investment in collectively reserved loans	2,862,602		2,859,608
Total recorded investment in loans	3,039,240		3,047,794
Single-family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	26,404		31,200
Allowance for loan losses for collectively reserved loans	2,461		3,977
Total allowance for loan losses	28,865	30,876	35,177	36,570	38,643	43,307
Recorded investment in individually impaired loans	175,479		186,377
Recorded investment in collectively reserved loans	2,665,062		2,672,184
Total recorded investment in loans	2,840,541		2,858,561
Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	113		175
Allowance for loan losses for collectively reserved loans	157		189
Total allowance for loan losses	270	$ 274	364	$ 361	$ 424	$ 539
Recorded investment in individually impaired loans	1,159		1,809
Recorded investment in collectively reserved loans	197,540		187,424
Total recorded investment in loans	$ 198,699		$ 189,233