Financial Instruments and Derivative Instruments (Details) (Fair value measured on a recurring basis, USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Fair Value Measurements at Reporting Date
Financial assets, cash flow hedges	$ 0	$ 0
Financial liabilities, cash flow hedges	0	0
Total
Assets
Plan asset for deferred compensation	4.3	4.2
Total assets	4.3	4.2
Liabilities
Plan liability for deferred compensation	4.3	4.2
Contingent consideration	5.0	5.2
Total liabilities	9.3	9.4
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Plan asset for deferred compensation	4.3	4.2
Total assets	4.3	4.2
Liabilities
Plan liability for deferred compensation	4.3	4.2
Total liabilities	4.3	4.2
Significant Unobservable Inputs (Level 3)
Liabilities
Contingent consideration	5.0	5.2
Total liabilities	$ 5.0	$ 5.2