Repurchase Arrangements And Similar Borrowings, Including Related Hedging Activity (Schedule Of Swap Agreements Expiration Period And Characteristics) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2010	Mar. 31, 2008	Jun. 30, 2011 Third Quarter 2011 [Member] Currently-Paying Contracts [Member]	Jun. 30, 2011 Fourth Quarter 2011 [Member] Currently-Paying Contracts [Member]	Jun. 30, 2011 First Quarter 2012 [Member] Currently-Paying Contracts [Member]	Jun. 30, 2011 Third Quarter 2012 [Member] Currently-Paying Contracts [Member]	Jun. 30, 2011 First Quarter 2013 [Member] Currently-Paying Contracts [Member]	Jun. 30, 2011 Second Quarter 2013 [Member] Currently-Paying Contracts [Member]	Jun. 30, 2011 Third Quarter 2013 [Member] Forward-Starting Contracts [Member]	Jun. 30, 2011 Fourth Quarter 2013 [Member] Forward-Starting Contracts [Member]	Jun. 30, 2011 Currently-Paying Contracts [Member]	Jun. 30, 2011 Forward-Starting Contracts [Member]
Notional Amount		$ 100,000	$ 400,000	$ 900,000	$ 800,000	$ 200,000	$ 1,100,000	$ 700,000	$ 300,000	$ 500,000	$ 4,100,000	$ 4,900,000
Average Fixed Rate Payment Requirement	4.09%		1.33%	1.15%	1.10%	0.83%	0.81%	0.96%	0.87%	0.78%	1.02%