Stock- Based Compensation Plans (Details 11) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Schedule of total intrinsic value of stock appreciation rights exercised
Realized tax benefits from tax deductions	$ 1.4	$ 5.3	$ 4.9
Stock Appreciation Rights [Member]
Schedule of total intrinsic value of stock appreciation rights exercised
Intrinsic value of stock appreciation rights exercised	4.2	10.1	1.5
Realized tax benefits from tax deductions	$ 1.6	$ 3.9	$ 0.6

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph g(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(1)(i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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