Fair Value Measurement of Assets and Liabilities (Details) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Available-for-sale securities
Available-for-sale Securities, Fair Value	$ 586.1	$ 410.6
Interest Rate Swap [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities
Derivatives, current and long-term	26.7	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	26.7	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	16.0	34.5
Liabilities
Derivatives, current and long-term	34.5	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	16.0	34.5
Liabilities
Derivatives, current and long-term	34.5	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	11.2
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	11.2
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	308.6	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	308.6	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	83.9	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	83.9	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	135.6	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	135.6	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	49.5	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	49.5	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	586.1	410.6
Total fair value measurement of assets	628.8	446.6
Liabilities
Total fair value measurement of liabilities	45.7	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	586.1	410.6
Total fair value measurement of assets	628.8	446.6
Liabilities
Total fair value measurement of liabilities	45.7	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