Revenue Reserves (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Analysis of the amount of, and change in, reserves
Beginning balance	$ 662.7	$ 483.8	$ 426.2
Current provisions relating to sales in current year	2,668.0	2,229.4	1,651.8
Adjustments relating to prior years	(16.7)	(32.3)	(16.0)
Payments/returns relating to sales in current year	(2,099.5)	(1,666.6)	(1,237.2)
Payments/returns relating to sales in prior years	(609.0)	(351.6)	(341.0)
Ending balance	605.5	662.7	483.8
Discounts
Analysis of the amount of, and change in, reserves
Beginning balance	56.1	47.6	47.0
Current provisions relating to sales in current year	592.6	459.7	347.3
Adjustments relating to prior years	(1.4)	(1.3)	(1.0)
Payments/returns relating to sales in current year	(522.5)	(405.9)	(299.7)
Payments/returns relating to sales in prior years	(53.2)	(44.0)	(46.0)
Ending balance	71.6	56.1	47.6
Contractual Adjustments
Analysis of the amount of, and change in, reserves
Beginning balance	548.7	387.1	345.5
Current provisions relating to sales in current year	2,044.5	1,732.1	1,265.4
Adjustments relating to prior years	1.5	(16.3)	(28.5)
Payments/returns relating to sales in current year	(1,576.0)	(1,258.1)	(933.4)
Payments/returns relating to sales in prior years	(536.0)	(296.1)	(261.9)
Ending balance	482.7	548.7	387.1
Returns
Analysis of the amount of, and change in, reserves
Beginning balance	57.9	49.1	33.7
Current provisions relating to sales in current year	30.9	37.6	39.1
Adjustments relating to prior years	(16.8)	(14.7)	13.5
Payments/returns relating to sales in current year	(1.0)	(2.6)	(4.1)
Payments/returns relating to sales in prior years	(19.8)	(11.5)	(33.1)
Ending balance	$ 51.2	$ 57.9	$ 49.1