Allowance for Loan Losses and Total Recorded Investment in HFI Loans (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	$ 23,794	$ 25,517
Allowance for loan losses for collectively reserved loans	2,025	2,434
Total allowance for loan losses	25,819	27,951	$ 31,820	$ 35,541
Recorded investment in individually impaired loans	169,206	172,169
Recorded investment in collectively reserved loans	2,871,011	2,863,543
Total recorded investment in loans	3,040,217	3,035,712
Single-family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	23,723	25,437
Allowance for loan losses for collectively reserved loans	1,874	2,272
Total allowance for loan losses	25,597	27,709	31,514	35,177
Recorded investment in individually impaired loans	168,284	171,161
Recorded investment in collectively reserved loans	2,663,977	2,664,377
Total recorded investment in loans	2,832,261	2,835,538
Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	71	80
Allowance for loan losses for collectively reserved loans	151	162
Total allowance for loan losses	222	242	$ 306	$ 364
Recorded investment in individually impaired loans	922	1,008
Recorded investment in collectively reserved loans	207,034	199,166
Total recorded investment in loans	$ 207,956	$ 200,174