Fair Value Measurement of Assets and Liabilities (Details) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Available-for-sale securities
Available-for-sale Securities, Fair Value	$ 425.7	$ 410.6
Interest Rate Swap [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities
Derivatives, current and long-term	5.5	1.5
Interest Rate Swap [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Available-for-sale securities
Derivatives, current and long-term	0	0
Interest Rate Swap [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member]
Available-for-sale securities
Derivatives, current and long-term	5.5	1.5
Interest Rate Swap [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member]
Available-for-sale securities
Derivatives, current and long-term	0	0
Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities
Derivatives, current and long-term	6.8	34.5
Liabilities
Derivatives, current and long-term	61.9	40.0
Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Available-for-sale securities
Derivatives, current and long-term	0	0
Liabilities
Derivatives, current and long-term	0	0
Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member]
Available-for-sale securities
Derivatives, current and long-term	6.8	34.5
Liabilities
Derivatives, current and long-term	61.9	40.0
Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member]
Available-for-sale securities
Derivatives, current and long-term	0	0
Liabilities
Derivatives, current and long-term	0	0
Cross Currency Interest Rate Contract [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities
Derivatives, current and long-term	3.3
Cross Currency Interest Rate Contract [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Liabilities
Derivatives, current and long-term	0
Cross Currency Interest Rate Contract [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member]
Liabilities
Derivatives, current and long-term	3.3
Cross Currency Interest Rate Contract [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member]
Liabilities
Derivatives, current and long-term	0
Corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	240.6	203.8
Corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	0	0
Corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	240.6	203.8
Corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	0	0
U.S. Government Agencies and Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	37.9	47.9
U.S. Government Agencies and Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	0	0
U.S. Government Agencies and Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	37.9	47.9
U.S. Government Agencies and Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	0	0
Municipal Bonds [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	1.0	1.1
Municipal Bonds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	0	0
Municipal Bonds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	1.0	1.1
Municipal Bonds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	0	0
Foreign government debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	7.5	10.3
Foreign government debt securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	0	0
Foreign government debt securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	7.5	10.3
Foreign government debt securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	0	0
Certificates of deposit [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	129.2	131.4
Certificates of deposit [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	0	0
Certificates of deposit [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	129.2	131.4
Certificates of deposit [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	0	0
Commercial Paper [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	9.5	16.1
Commercial Paper [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	0	0
Commercial Paper [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	9.5	16.1
Commercial Paper [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	0	0
Fair Value, Measurements, Recurring [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	425.7	410.6
Total fair value measurement of assets	438.0	446.6
Liabilities
Total fair value measurement of liabilities	65.2	40.0
Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	0	0
Total fair value measurement of assets	0	0
Liabilities
Total fair value measurement of liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	425.7	410.6
Total fair value measurement of assets	438.0	446.6
Liabilities
Total fair value measurement of liabilities	65.2	40.0
Fair Value, Measurements, Recurring [Member] | Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member]
Available-for-sale securities
Available-for-sale Securities, Fair Value	0	0
Total fair value measurement of assets	0	0
Liabilities
Total fair value measurement of liabilities	$ 0	$ 0