Fair Value Measurements (Details) (Recurring, USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Level 1
Assets:
Money market funds held in rabbi trusts	$ 2.1	$ 2.2
Level 2
Assets:
Foreign currency forward contracts	12.1	6.5
Liabilities:
Foreign currency forward contracts	12.7	9.9
Level 3
Liabilities:
Contingent consideration obligation	13.7	23.2
Carrying Amount
Assets:
Money market funds held in rabbi trusts	2.1	2.2
Foreign currency forward contracts	12.1	6.5
Liabilities:
Foreign currency forward contracts	12.7	9.9
Contingent consideration obligation	$ 13.7	$ 23.2