Fair Value Measurement (Assets and Liabilities Measured on a Recurring Basis) (Details) - Recurring Basis - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securities	$ 70.8	$ 65.8
Marketable debt securities	3.5	3.6
Contingent consideration receivable	0.0	0.0
Derivative instruments	0.0	0.0
Total assets	74.3	69.4
Joint venture net written option	0.0
Derivative instruments	0.0	0.0
Contingent consideration payable	0.0	0.0
Total liabilities	0.0	0.0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securities	0.0	0.0
Marketable debt securities	12.0	11.9
Contingent consideration receivable	0.0	0.0
Derivative instruments	9.9	18.0
Total assets	21.9	29.9
Joint venture net written option	0.0
Derivative instruments	9.9	8.3
Contingent consideration payable	0.0	0.0
Total liabilities	9.9	8.3
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securities	0.0	0.0
Marketable debt securities	0.0	0.0
Contingent consideration receivable	16.5	15.6
Derivative instruments	0.0	0.0
Total assets	16.5	15.6
Joint venture net written option	25.0
Derivative instruments	0.0	0.0
Contingent consideration payable	1,051.2	1,058.0
Total liabilities	1,076.2	1,058.0
Fair value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securities	70.8	65.8
Marketable debt securities	15.5	15.5
Contingent consideration receivable	16.5	15.6
Derivative instruments	9.9	18.0
Total assets	112.7	114.9
Joint venture net written option	25.0
Derivative instruments	9.9	8.3
Contingent consideration payable	1,051.2	1,058.0
Total liabilities	$ 1,086.1	$ 1,066.3