Commitments And Contingencies (Schedule Of Repurchase Agreements) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Commitments and Contingencies Disclosure [Abstract]
Aggregate fair value of indemnified securities financing	$ 323,429	$ 302,342
Aggregate fair value of cash and securities held as collateral for indemnified securities financing	334,664	312,598
Aggregate fair value of collateral for indemnified securities financing invested in indemnified repurchase agreements	94,450	88,656
Aggregate fair value of cash and securities held as collateral for indemnified repurchase agreements	$ 99,546	$ 93,039