Fair Value Measurements of Assets and Liabilities - Fair Value Measurements of Assets and Liabilities (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	$ 807.7	$ 915.7
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	807.7	915.7
Total fair value measurement of assets	892.7	978.0
Total fair value measurement of liabilities	27.6
Fair Value, Measurements, Recurring [Member] | Foreign exchange forward contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, current and long-term	68.7	28.4
Derivatives, current and long-term	20.6	10.8
Fair Value, Measurements, Recurring [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, current and long-term	16.3	33.9
Derivatives, current and long-term	7.0
Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	457.9	383.8
Fair Value, Measurements, Recurring [Member] | U.S. government and agency debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	211.2	295.9
Fair Value, Measurements, Recurring [Member] | Foreign government debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	3.1	5.0
Fair Value, Measurements, Recurring [Member] | Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	68.3	138.7
Fair Value, Measurements, Recurring [Member] | Certificates of deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	67.2	92.3
Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value
Total fair value measurement of assets
Total fair value measurement of liabilities
Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Foreign exchange forward contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, current and long-term
Derivatives, current and long-term
Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, current and long-term
Derivatives, current and long-term
Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value
Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | U.S. government and agency debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value
Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Foreign government debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value
Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value
Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Certificates of deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value
Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	807.7	915.7
Total fair value measurement of assets	892.7	978.0
Total fair value measurement of liabilities	27.6
Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Foreign exchange forward contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, current and long-term	68.7	28.4
Derivatives, current and long-term	20.6	10.8
Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, current and long-term	16.3	33.9
Derivatives, current and long-term	7.0
Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	457.9	383.8
Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | U.S. government and agency debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	211.2	295.9
Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Foreign government debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	3.1	5.0
Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	68.3	138.7
Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Certificates of deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	67.2	92.3
Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value
Total fair value measurement of assets
Total fair value measurement of liabilities
Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Foreign exchange forward contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, current and long-term
Derivatives, current and long-term
Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, current and long-term
Derivatives, current and long-term
Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value
Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | U.S. government and agency debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value
Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Foreign government debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value
Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value
Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Certificates of deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value