Reserves for Discounts and Allowances (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 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	146.1
Adjustments relating to prior years	(3.1)
Payments/returns relating to sales in current year	(44.1)
Payments/returns relating to sales in prior years	(73.8)
Balance, as of March 31, 2012	180.7
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	26.0
Adjustments relating to prior years	(0.3)
Payments/returns relating to sales in current year	(12.7)
Payments/returns relating to sales in prior years	(10.8)
Balance, as of March 31, 2012	14.8
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	109.8
Adjustments relating to prior years	(3.5)
Payments/returns relating to sales in current year	(31.3)
Payments/returns relating to sales in prior years	(60.7)
Balance, as of March 31, 2012	133.6
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	10.3
Adjustments relating to prior years	0.7
Payments/returns relating to sales in current year	(0.1)
Payments/returns relating to sales in prior years	(2.3)
Balance, as of March 31, 2012	$ 32.3