Fair Value Measurements, Assets and Liabilities (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Assets
Cash equivalents	$ 60.7	$ 377.1
Investments in mutual funds, unit trusts and other similar instruments	35.5	35.6
Insurance contracts	58.0	56.7
Auction rate securities	4.3	4.3
Derivative contracts	1.6	0.9
Total Assets	160.1	474.6
Liabilities
Derivative contracts	4.5	1.2
Contingent consideration	4.6	1.7
Total Liabilities	9.1	2.9
Quoted Prices in Active Markets (Level I) [Member]
Assets
Cash equivalents	60.7	377.1
Investments in mutual funds, unit trusts and other similar instruments	35.5	35.6
Total Assets	96.2	412.7
Significant Other Observable Inputs (Level 2) [Member]
Assets
Insurance contracts	58.0	56.7
Derivative contracts	1.6	0.9
Total Assets	59.6	57.6
Liabilities
Derivative contracts	4.5	1.2
Total Liabilities	4.5	1.2
Significant Unobservable Inputs (Level 3) [Member]
Assets
Auction rate securities	4.3	4.3
Total Assets	4.3	4.3
Liabilities
Contingent consideration	4.6	1.7
Total Liabilities	$ 4.6	$ 1.7