Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 3.8		$ 2.0	$ 1.8	$ 0.7
Assets, Fair Value Disclosure [Abstract]
Business Combination, Contingent Consideration, Liability	7.2	24.3
Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Available for sale securities	3.8		2.0
Trading securities	2.0		1.7
Business Combination, Contingent Consideration, Liability	(7.2)
Total	13.0		3.7
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets, Fair Value Disclosure [Abstract]
Available for sale securities	0		0
Trading securities	2.0		1.7
Business Combination, Contingent Consideration, Liability	0
Total	2.0		1.7
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Available for sale securities	0		0
Trading securities	0		0
Business Combination, Contingent Consideration, Liability	0
Total	0		0
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets, Fair Value Disclosure [Abstract]
Available for sale securities	3.8		2.0
Trading securities	0		0
Business Combination, Contingent Consideration, Liability	(7.2)
Total	$ 11.0		$ 2.0