Summary of Significant Accounting Policies (Details) (USD $) In Millions	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Supplemental cash flow information - Noncash activities
Transfers from loans to securities available for sale	$ 0	$ 3,468
Trading assets retained from securitization of MHFS	18,393
Capitalization of MSRs from sale of MHFS	2,058	2,025
Transfers from MHFS to foreclosed assets	78	102
Transfers from (to) loans (from) to MHFS	50	99
Transfers from (to) loans (from) to LHFS	170	(77)
Transfers from loans to foreclosed assets	2,164	5,481
Changes in consolidations of variable interest entities
Trading assets	0	155
Securities available for sale	156	(7,590)
Loans	(1,004)	25,657
Other assets	0	193
Short-term borrowings	0	5,127
Long-term debt	(770)	13,134
Accrued expenses and other liabilities	0	(32)
Decrease in noncontrolling interests due to deconsolidation of subsidiaries	0	240
Transfer from noncontrolling interests to long term debt	$ 0	$ 345