Commitments and Contingencies (Schedule of Repurchase Agreements) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2011		Dec. 31, 2010
Commitments and Contingencies
Aggregate fair value of indemnified securities financing	$ 357,854		$ 334,235
Aggregate fair value of cash and securities held as collateral for indemnified securities financing	367,471		343,410
Aggregate fair value of collateral for indemnified securities financing invested in indemnified repurchase agreements	95,277	[1]	89,069	[1]
Aggregate fair value of cash and securities held as collateral for indemnified repurchase agreements	$ 99,834		$ 93,294
Percent of fair market value that must be maintained in collateral	100.00%

[1] We require the counterparty to the indemnified repurchase agreement to provide collateral in an amount equal to or in excess of 100% of the amount of the repurchase obligation.