Segment Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue, Major Customer [Line Items]
Product Revenues	$ 3,526.3	$ 3,439.0	$ 3,356.5	$ 3,131.1	$ 3,307.0	$ 3,077.8	$ 3,078.4	$ 2,810.7	$ 13,452.9	$ 12,273.9	$ 11,448.8
Geographic information
Long-lived assets	3,601.2				3,182.4				3,601.2	3,182.4	2,501.8
U.S
Geographic information
Long-lived assets	1,152.7				1,226.9				1,152.7	1,226.9	1,272.3
Europe
Geographic information
Long-lived assets	2,442.8				1,948.2				2,442.8	1,948.2	1,221.1
Asia
Geographic information
Long-lived assets	3.9				5.2				3.9	5.2	7.0
Other
Geographic information
Long-lived assets	1.8				2.1				1.8	2.1	1.4
Revenues from anti-cd20 therapeutic programs
Revenue, Major Customer [Line Items]
Product Revenues	534.9	511.7	490.4	443.2	415.0	406.5	397.1	340.6	1,980.2	1,559.2	1,314.5
Revenues from anti-cd20 therapeutic programs | U.S
Revenue, Major Customer [Line Items]
Product Revenues									1,903.4	1,475.6	1,249.5
Revenues from anti-cd20 therapeutic programs | Europe
Revenue, Major Customer [Line Items]
Product Revenues									0.2	0.6	1.9
Revenues from anti-cd20 therapeutic programs | Asia
Revenue, Major Customer [Line Items]
Product Revenues									0.0	0.0	0.0
Revenues from anti-cd20 therapeutic programs | Other
Revenue, Major Customer [Line Items]
Product Revenues									76.6	83.0	63.1
Other revenue
Revenue, Major Customer [Line Items]
Product Revenues	165.7	147.2	108.6	164.4	179.6	48.8	41.6	90.0	585.9	360.0	316.4
Other revenue | U.S
Revenue, Major Customer [Line Items]
Product Revenues									457.0	249.5	224.7
Other revenue | Europe
Revenue, Major Customer [Line Items]
Product Revenues									32.7	67.8	71.5
Other revenue | Asia
Revenue, Major Customer [Line Items]
Product Revenues									96.2	42.7	20.2
Other revenue | Other
Revenue, Major Customer [Line Items]
Product Revenues									0.0	0.0	0.0
Product, net
Revenue, Major Customer [Line Items]
Product Revenues	$ 2,825.7	$ 2,780.1	$ 2,757.5	$ 2,523.5	$ 2,712.4	$ 2,622.5	$ 2,639.7	$ 2,380.1	10,886.8	10,354.7	9,817.9
Product, net | U.S
Revenue, Major Customer [Line Items]
Product Revenues									6,800.5	7,017.1	7,050.4
Product, net | Europe
Revenue, Major Customer [Line Items]
Product Revenues									3,370.3	2,844.8	2,237.2
Product, net | Asia
Revenue, Major Customer [Line Items]
Product Revenues									281.2	160.1	217.3
Product, net | Other
Revenue, Major Customer [Line Items]
Product Revenues									$ 434.8	$ 332.7	$ 313.0