Fair Values Of Assets And Liabilities Fair Value of Assets and Liabilities (Narrative) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amount Exluded From Money Market Funds	$ 263.0	$ 252.7