Share Repurchase Share Repurchase (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Shareowners' Deficit [Abstract]
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 129.2
Stock Repurchase Program, Authorized Amount			150.0
Stock Repurchased During Period, Shares		3.4
Stock Repurchased During Period, Value		10.8	10.0
Treasury Stock, Shares, Retired	0.1
Stock Repurchased and Retired During Period, Shares		3.3
Treasury Stock, Retired, Amount	$ 0.3

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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- Definition

Equity impact of the par value of shares of common and preferred stock retired from treasury during the period. This element is used only when Treasury Stock is accounted for under the cost versus the par value method.

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