Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2012

Fair Value Measurements [Abstract]

Fair Value Of Assets And Liabilities Measured On Recurring Basis

	March 31, 2012								December 31, 2011
	Fair Value Asset (Liability)								Fair Value Asset (Liability)
(in millions)	Level 1		Level 2			Total			Level 1		Level 2			Total
Derivatives:
Assets	$	—	$	0.7		$	0.7		$	—	$	4.4		$	4.4
Liabilities		—		(7.5	)		(7.5	)		—		(8.6	)		(8.6	)
Available for sale securities		—		21.0			21.0			—		19.5			19.5