Fair Value Measurements (Details 1) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Notes payable, carrying value	$ 5,932.7	$ 5,938.2
Debt instruments, fair value	6,188.3	6,483.3
Notes Payable to Fumedica
Debt Instrument [Line Items]
Notes payable, fair value	3.3	3.2
Notes payable, carrying value	3.3	3.2
2.900% Senior Notes due 2020
Debt Instrument [Line Items]
Notes payable, fair value	1,490.7	1,517.7
Notes payable, carrying value	1,476.0	1,482.4
3.625% Senior Notes due 2022
Debt Instrument [Line Items]
Notes payable, fair value	1,007.3	1,032.9
Notes payable, carrying value	994.6	994.3
4.050% Senior Notes due 2025
Debt Instrument [Line Items]
Notes payable, fair value	1,788.8	1,851.9
Notes payable, carrying value	1,736.7	1,736.3
5.200% Senior Notes due 2045
Debt Instrument [Line Items]
Notes payable, fair value	1,898.2	2,077.6
Notes payable, carrying value	$ 1,722.1	$ 1,722.0