Counterparty Risk (Tables)

6 Months Ended

Jun. 30, 2012

Counterparty Risk [Abstract]

% Of Total Collateral On Reverse Repurchase Agreements

	% of Total Collateral on
	Reverse Repurchase
Dealer	Agreements
Credit Suisse Group	20	%
J.P. Morgan Securities Inc.	20	%
Deutsche Bank	16	%

% Of Total Deposits With Dealers Held As Collateral

	% of Total Deposits with
	Dealers Held as
Dealer	Collateral
Citigroup	38	%
Bank of America	30	%

% Of Total Receivable For Securities Sold

	% of Total Receivable for
Dealer	Securities Sold
CS First Boston	35	%
Royal Bank of Scotland	26	%