Allowance for Loan Losses Allowance at Recorded Investment (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Mar. 31, 2013	Dec. 31, 2012		Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	$ 40,583	[1]		$ 45,034	[1]
Allowance for loan losses for collectively reserved loans	9,060			13,761
Allowance for loan losses	49,643		56,461	58,795		63,375	70,109	72,156
Recorded investment in individually impaired loans	194,896	[1],[2]		200,391	[1],[2]
Recorded investment in collectively reserved loans	2,826,520	[2]		2,807,080	[2]
Total recorded investment	3,021,416	[2]		3,007,471	[2]
Single-Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	40,131	[1]		44,545	[1]
Allowance for loan losses for collectively reserved loans	8,639			13,142
Allowance for loan losses	48,770		55,501	57,687		62,134	68,738	70,633
Recorded investment in individually impaired loans	190,197	[1],[2]		195,852	[1],[2]
Recorded investment in collectively reserved loans	2,640,683	[2]		2,620,568	[2]
Total recorded investment	2,830,880	[2]		2,816,420	[2]
Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	452	[1]		489	[1]
Allowance for loan losses for collectively reserved loans	421			619
Allowance for loan losses	873		960	1,108		1,241	1,371	1,523
Recorded investment in individually impaired loans	4,699	[1],[2]		4,539	[1],[2]
Recorded investment in collectively reserved loans	185,837	[2]		186,512	[2]
Total recorded investment	$ 190,536	[2],[3],[4]		$ 191,051	[2],[3],[4]

[1] Includes acquired credit-impaired loans.

[2] Recorded investment consists of unpaid principal balance, unamortized premiums, discounts and other cost basis adjustments, and accrued interest receivable.

[3] Multifamily loans 60-89 days delinquent are included in the seriously delinquent column.

[4] Green (loan with acceptable risk); yellow (loan with signs of potential weakness); orange (loan with a well defined weakness that may jeopardize the timely full repayment); and red (loan with a weakness that makes timely collection or liquidation in full more questionable based on existing conditions and values).