Securities Available For Sale (Auction Rate Securities Reconciliation Of Cost Basis To Fair Value) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010		Jul. 31, 2008
Adjusted cost basis	$ 14.6	[1]	$ 19.8	[1]
Gross Cumulative Unrealized (Losses)/Gains	(1.0)		(0.8)
Fair Value	13.6		19.0
Auction Rate Securities [Member]
Cumulative credit and other losses recognized in earnings	3.3		2.7
Par Value of Securities Held	17.9		22.5		33.7
Structured Finance Securities [Member] | Auction Rate Securities [Member]
Adjusted cost basis	1.7	[1]	2.3	[1]
Gross Cumulative Unrealized (Losses)/Gains			0.3
Fair Value	1.7		2.6
Cumulative credit and other losses recognized in earnings	3.3
Par Value of Securities Held	5.0
Asset Backed Securities [Member] | Auction Rate Securities [Member]
Adjusted cost basis	12.9	[1]	17.5	[1]
Gross Cumulative Unrealized (Losses)/Gains	(1.0)		(1.1)
Fair Value	$ 11.9		$ 16.4

[1] Adjusted cost basis reflects adjustments for credit and other losses recognized in earnings. Cumulative adjustments to the cost basis of securities held as of December 31, 2011 and 2010 totaled $3.3 million and $2.7 million, respectively. Par value of securities held as of December 31, 2011 and 2010 was $17.9 million and $22.5 million, respectively.