Fair Value Measurement of Assets and Liabilities (Tables)

6 Months Ended

Jun. 30, 2013

Fair Value Disclosures [Abstract]

Fair Value Measurements of Assets and Liabilities

The following assets and liabilities are recorded at fair value on a recurring basis (in millions):

	As of June 30, 2013
			Fair Value Measurements at Reporting Date Using:
Description	Recorded Balance		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Available-for-sale securities
Corporate debt securities	$	392.0	$	—	$	392.0	$	—
U.S. government and agency debt securities		271.6		—		271.6		—
Commercial paper		49.0		—		49.0		—
Certificates of deposit		87.5		—		87.5		—
Total available-for-sale securities		800.1		—		800.1		—
Derivatives, current and long-term
Foreign currency forward contracts and options		74.2		—		74.2		—
Interest rate swaps		19.8		—		19.8		—
	$	894.1	$	—	$	894.1	$	—
Liabilities
Derivatives, current and long-term
Foreign currency forward contracts and options	$	2.2	$	—	$	2.2	$	—

	As of December 31, 2012
			Fair Value Measurements at Reporting Date Using:
Description	Recorded Balance		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Available-for-sale securities
Corporate debt securities	$	383.8	$	—	$	383.8	$	—
U.S. government and agency debt securities		295.9		—		295.9		—
Foreign government debt securities		5.0		—		5.0		—
Commercial paper		138.7		—		138.7		—
Certificates of deposit		92.3		—		92.3		—
Total available-for-sale securities		915.7		—		915.7		—
Derivatives, current and long-term
Foreign currency forward contracts and options		28.4		—		28.4		—
Interest rate swaps		33.9		—		33.9		—
	$	978.0	$	—	$	978.0	$	—
Liabilities
Derivatives, current and long-term
Foreign currency forward contracts and options	$	10.8	$	—	$	10.8	$	—