Revenue Reserves (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Analysis of the amount of, and change in, reserves
Beginning balance	$ 142.0	$ 103.1	$ 75.4
Current provisions relating to sales in current year	472.1	381.7	282.3
Adjustments relating to prior years	(14.9)	(6.9)	0.8
Payments/returns relating to sales in current year	(350.7)	(253.8)	(185.8)
Payments/returns relating to sales in prior years	(92.9)	(82.1)	(69.6)
Ending balance	155.6	142.0	103.1
Discounts [Member]
Analysis of the amount of, and change in, reserves
Beginning balance	13.9	13.9	9.2
Current provisions relating to sales in current year	96.0	80.6	74.0
Adjustments relating to prior years	0	(2.7)
Payments/returns relating to sales in current year	(84.3)	(68.7)	(60.8)
Payments/returns relating to sales in prior years	(13.0)	(9.2)	(8.5)
Ending balance	12.6	13.9	13.9
Contractual Adjustments [Member]
Analysis of the amount of, and change in, reserves
Beginning balance	107.0	70.3	48.1
Current provisions relating to sales in current year	360.4	285.0	192.5
Adjustments relating to prior years	(14.0)	(2.4)
Payments/returns relating to sales in current year	(266.0)	(184.3)	(124.4)
Payments/returns relating to sales in prior years	(68.1)	(61.6)	(45.9)
Ending balance	119.3	107.0	70.3
Returns [Member]
Analysis of the amount of, and change in, reserves
Beginning balance	21.1	18.9	18.1
Current provisions relating to sales in current year	15.7	16.1	15.8
Adjustments relating to prior years	(0.9)	(1.8)	0.8
Payments/returns relating to sales in current year	(0.4)	(0.8)	(0.6)
Payments/returns relating to sales in prior years	(11.8)	(11.3)	(15.2)
Ending balance	$ 23.7	$ 21.1	$ 18.9