Fair Value Measurement (Assets and Liabilities That are Measured and Not Measured at Fair Value on a Recurring Basis) (Details) (Recurring Basis, USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013
Carrying value
Financial assets:
Available-for-sale securities	$ 13.2	[1]	$ 6.7	[1]
Contingent consideration receivable	57.5	[2]	36.1	[2]
Foreign exchange contracts, asset	7.3		4.0
Financial liabilities:
Foreign exchange contracts, liability	1.2		2.8
Contingent consideration payable	591.8	[3]	405.9	[3]
Estimated fair value
Financial assets:
Available-for-sale securities	13.2	[1]	6.7	[1]
Contingent consideration receivable	57.5	[2]	36.1	[2]
Foreign exchange contracts, asset	7.3		4.0
Financial liabilities:
Foreign exchange contracts, liability	1.2		2.8
Contingent consideration payable	591.8	[3]	405.9	[3]
Level 1
Financial assets:
Available-for-sale securities	13.2	[1]	6.7	[1]
Contingent consideration receivable	0	[2]	0	[2]
Foreign exchange contracts, asset	0		0
Financial liabilities:
Foreign exchange contracts, liability	0		0
Contingent consideration payable	0	[3]	0	[3]
Level 2
Financial assets:
Available-for-sale securities	0	[1]	0	[1]
Contingent consideration receivable	0	[2]	0	[2]
Foreign exchange contracts, asset	7.3		4.0
Financial liabilities:
Foreign exchange contracts, liability	1.2		2.8
Contingent consideration payable	0	[3]	0	[3]
Level 3
Financial assets:
Available-for-sale securities	0	[1]	0	[1]
Contingent consideration receivable	57.5	[2]	36.1	[2]
Foreign exchange contracts, asset	0		0
Financial liabilities:
Foreign exchange contracts, liability	0		0
Contingent consideration payable	$ 591.8	[3]	$ 405.9	[3]

[1] Available-for-sale securities are included within Investments and Prepaid expenses and other current assets in the consolidated balance sheet.

[2] Contingent consideration receivable is included within Prepaid expenses and other current assets and Other non-current assets in the consolidated balance sheet.

[3] Contingent consideration payable is included within Other current liabilities and Other non-current liabilities in the consolidated balance sheet.