Commitments and Contingencies (Narrative) (Details)	3 Months Ended		6 Months Ended	12 Months Ended	84 Months Ended
	Sep. 30, 2010 USD ($)	Sep. 30, 2007	Jun. 30, 2011 USD ($)	Dec. 31, 2007	Dec. 31, 2007 USD ($)	Jun. 30, 2011 EUR (€)	Dec. 31, 2010 USD ($)	Aug. 31, 2009 USD ($)	Sep. 15, 2008 USD ($) Cus	Jun. 30, 2007 USD ($)
Commitments and Contingencies
Percent of fair market value that must be maintained in collateral			100.00%
Net assets of registered sub-prime funds										$ 300,000,000
Average decline in net asset value per share		7.23%
Actual damages asserted by attorney general					56,000,000
Litigation reserve							75,000,000
Settlement with State of Washington	12,000,000
Number of years of relationships with State of Washington				ten
Net assets of a fund held by Lehman									312,000,000
Number of customer not entered into settlement agreements									5
Settlements with Dutch customers						42,000,000
Investment in funds by customers not settled									170,000,000
Unrecognized tax benefits			234,000,000				419,000,000
Decrease in unrecognized tax benefit over the next 12 months			158,000,000
Notional amount of contingencies accounted for as derivative financial instruments			43,150,000,000				46,760,000,000
Asserted damages by two participants in the agency securities lending program								120,000,000
The difference between the amortized cost and market value of the in-kind distribution	49,000,000		28,000,000
Cash contribution to the cash collateral pools and liquidity trusts							$ 330,000,000