Integration and Acquisition Costs (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Integration and acquisition costs (credits)	$ 93.0	$ 237.0	$ 512.0	$ 696.7
Baxalta
Business Acquisition [Line Items]
Integration and acquisition costs (credits)	93.0	237.0	512.0	696.7
Asset impairments | Baxalta
Business Acquisition [Line Items]
Integration and acquisition costs (credits)	8.0		151.4
Integration costs		114.1		147.8
Third-party professional fees | Baxalta
Business Acquisition [Line Items]
Integration and acquisition costs (credits)	12.4		55.5
Integration costs		28.4		114.0
Change in fair value of contingent consideration payable
Business Acquisition [Line Items]
Integration costs	54.5	3.4	100.4	144.3
Facility consolidations | Baxalta
Business Acquisition [Line Items]
Integration and acquisition costs (credits)	4.4		19.2
Integration costs		29.7		71.4
Employee severance and acceleration of stock compensation | Baxalta
Business Acquisition [Line Items]
Integration and acquisition costs (credits)	5.7		20.7
Integration costs		$ 60.2		$ 177.4
Takeda | Third-party professional fees
Business Acquisition [Line Items]
Integration and acquisition costs (credits)	8.0		72.0
Takeda | Severance and employee benefits
Business Acquisition [Line Items]
Integration and acquisition costs (credits)	$ 36.4		$ 40.4