Reserves for Discounts and Allowances (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Analysis of the amount of, and change in, reserves
Balance, as of December 31, 2011	$ 155.6
Current provisions relating to sales in current year	455.1
Adjustments relating to prior years	(5.8)
Payments/returns relating to sales in current year	(291.5)
Payments/returns relating to sales in prior years	(104.2)
Balance, as of June 30, 2012	209.2
Discounts [Member]
Analysis of the amount of, and change in, reserves
Balance, as of December 31, 2011	12.6
Current provisions relating to sales in current year	84.4
Adjustments relating to prior years	(0.2)
Payments/returns relating to sales in current year	(70.8)
Payments/returns relating to sales in prior years	(11.0)
Balance, as of June 30, 2012	15.0
Contractual Adjustments [Member]
Analysis of the amount of, and change in, reserves
Balance, as of December 31, 2011	119.3
Current provisions relating to sales in current year	353.4
Adjustments relating to prior years	(5.3)
Payments/returns relating to sales in current year	(217.4)
Payments/returns relating to sales in prior years	(83.2)
Balance, as of June 30, 2012	166.8
Returns [Member]
Analysis of the amount of, and change in, reserves
Balance, as of December 31, 2011	23.7
Current provisions relating to sales in current year	17.3
Adjustments relating to prior years	(0.3)
Payments/returns relating to sales in current year	(3.3)
Payments/returns relating to sales in prior years	(10.0)
Balance, as of June 30, 2012	$ 27.4