Allowance for Loan Losses and Total Recorded Investment in HFI Loans (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	$ 21,953	$ 25,517
Allowance for loan losses for collectively reserved loans	1,512	2,434
Total allowance for loan losses	23,465	27,951	$ 35,541	$ 43,846
Recorded investment in individually impaired loans	156,187	172,169
Recorded investment in collectively reserved loans	2,939,629	2,863,543
Total recorded investment in loans	3,095,816	3,035,712
Single-Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	21,920	25,437
Allowance for loan losses for collectively reserved loans	1,363	2,272
Total allowance for loan losses	23,283	27,709	35,177	43,307
Recorded investment in individually impaired loans	155,598	171,161
Recorded investment in collectively reserved loans	2,708,337	2,664,377
Total recorded investment in loans	2,863,935	2,835,538
Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	33	80
Allowance for loan losses for collectively reserved loans	149	162
Total allowance for loan losses	182	242	$ 364	$ 539
Recorded investment in individually impaired loans	589	1,008
Recorded investment in collectively reserved loans	231,292	199,166
Total recorded investment in loans	$ 231,881	$ 200,174