Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2012

Schedule Of Fair Value Of Financial Assets Measured On Recurring Basis

2012

	Quoted Prices in Active Markets (Level 1)		Other Observable Inputs (Level 2)		Unobservable Inputs (Level 3)		Total
Cash and cash equivalents	$	431.3	$	—	$	—	$	431.3
Restricted cash and cash equivalents — current		2.6		—		—		2.6
Restricted cash and cash equivalents — non-current		13.7		—		—		13.7
Available-for-sale equity securities — current		167.9		—		—		167.9
Total	$	615.5	$	—	$	—	$	615.5

2011

	Quoted Prices in Active Markets (Level 1)		Other Observable Inputs (Level 2)		Unobservable Inputs (Level 3)		Total
Cash and cash equivalents	$	271.7	$	—	$	—	$	271.7
Restricted cash — current		2.6		—		—		2.6
Restricted cash — non-current		13.7		—		—		13.7
Available-for-sale equity securities — current		0.3		—		—		0.3
Total	$	288.3	$	—	$	—	$	288.3

Summary Of Changes In Fair Value Of Level 3 Financial Assets Measured On Recurring Basis

2011

	Auction Rate Securities
Beginning balance at January 1, 2011	$	0.2
Realized gains included in net investment gains		—
Unrealized losses included in other comprehensive income		—
Disposals		(0.2	)
Ending balance at December 31, 2011	$	—

Schedule Of Principal Amounts And Fair Values Of Debt Instruments

	2012				2011
	Principal		Fair		Principal		Fair
	Amount		Value		Amount		Value
6.25% Notes	$	600.0	$	628.1	$	—	$	—
2016 Notes issued October 2009		—		—		472.1		503.4
2016 Notes issued August 2010		—		—		152.4		161.7
Total debt instruments	$	600.0	$	628.1	$	624.5	$	665.1