Other Income (Expense), Net (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Components of other income (expense) [Line Items]
Interest income	$ 0		$ 0.1		$ 0.1		$ 0.2
Unrealized (losses) gains on financial derivatives	(0.9)	[1]	0.7	[1]	(0.5)	[1]	1.2	[1]
Realized gains on investments	0.3		0.1		0.8		0.1
All other, net	(0.2)		0.2		(0.2)		0.3
Other non-operating (expense) income, net	$ (0.8)		$ 1.1		$ 0.2		$ 1.8

[1] See “Hedges Relating to the Convertible Notes” in Note 9 for discussion of such instruments.