Fair Value Measurements (Details 1) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument
Total fair value	$ 6,483.3	$ 6,808.4
Notes Payable to Fumedica
Debt Instrument
Notes payable, fair value	3.2	6.1
6.875% Senior Notes due 2018
Debt Instrument
Notes payable, fair value	0.0	583.7
2.90% Senior Notes due 2020
Debt Instrument
Notes payable, fair value	1,517.7	1,521.5
3.625% Senior Notes due 2022
Debt Instrument
Notes payable, fair value	1,032.9	1,026.6
4.05% Senior Notes due 2025
Debt Instrument
Notes payable, fair value	1,851.9	1,796.0
5.20% Senior Notes due 2045
Debt Instrument
Notes payable, fair value	$ 2,077.6	$ 1,874.5