Fair Value of Financial Instruments (Details) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Cash and cash equivalents [Abstract]
Cash	$ 422,400,000	$ 447,100,000
Certificates of deposit	200,000	200,000
Money market funds	436,800,000	429,100,000
Commercial paper	120,100,000	202,700,000
U.S. treasury securities	23,600,000	17,600,000
U.S. non-governmental agency asset-backed securities	71,300,000	99,500,000
U.S. corporate obligations	45,300,000	18,900,000
Non-U.S. bank and other obligations	22,400,000	28,800,000
Short-term investments [Abstract]
Certificates of deposit	2,300,000	3,000,000
Commercial paper	255,800,000	253,900,000
U.S. Treasury securities	89,400,000	64,500,000
U.S. non-governmental agency asset-backed securities	11,600,000	41,400,000
U.S. corporate obligations	110,100,000	96,100,000
Non-qualified plan assets [Abstract]
Money market funds	1,000,000	1,100,000
Domestic bond funds	2,600,000	2,400,000
International bond fund	100,000	100,000
Domestic equity funds	4,300,000	3,600,000
International equity funds	2,200,000	2,100,000
Blended equity funds	3,000,000	2,600,000
Common stock	3,400,000	2,100,000
Derivatives, net asset (liability) [Abstract]
Foreign currency contracts	(8,300,000)	19,900,000
Total financial instruments	1,619,600,000	1,736,700,000
Fair value of the fixed-rate debt	2,030,000,000	2,060,000,000
Face value of the fixed-rate debt	1,750,000,000	1,750,000,000
Fair Value Based on Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Cash and cash equivalents [Abstract]
Cash	422,400,000	447,100,000
Certificates of deposit	200,000	200,000
Money market funds	436,800,000	429,100,000
Commercial paper	0	0
U.S. treasury securities	23,600,000	17,600,000
U.S. non-governmental agency asset-backed securities	0	0
U.S. corporate obligations	45,300,000	18,900,000
Non-U.S. bank and other obligations	22,400,000	28,800,000
Short-term investments [Abstract]
Certificates of deposit	2,300,000	3,000,000
Commercial paper	0	0
U.S. Treasury securities	89,400,000	64,500,000
U.S. non-governmental agency asset-backed securities	0	0
U.S. corporate obligations	110,100,000	96,100,000
Non-qualified plan assets [Abstract]
Money market funds	1,000,000	1,100,000
Domestic bond funds	2,600,000	2,400,000
International bond fund	100,000	100,000
Domestic equity funds	4,300,000	3,600,000
International equity funds	2,200,000	2,100,000
Blended equity funds	3,000,000	2,600,000
Common stock	3,400,000	2,100,000
Derivatives, net asset (liability) [Abstract]
Foreign currency contracts	0	0
Total financial instruments	1,169,100,000	1,119,300,000
Fair Value Based on Significant Other Observable Inputs (Level 2) [Member]
Cash and cash equivalents [Abstract]
Cash	0	0
Certificates of deposit	0	0
Money market funds	0	0
Commercial paper	120,100,000	202,700,000
U.S. treasury securities	0	0
U.S. non-governmental agency asset-backed securities	71,300,000	99,500,000
U.S. corporate obligations	0	0
Non-U.S. bank and other obligations	0	0
Short-term investments [Abstract]
Certificates of deposit	0	0
Commercial paper	255,800,000	253,900,000
U.S. Treasury securities	0	0
U.S. non-governmental agency asset-backed securities	11,600,000	41,400,000
U.S. corporate obligations	0	0
Non-qualified plan assets [Abstract]
Money market funds	0	0
Domestic bond funds	0	0
International bond fund	0	0
Domestic equity funds	0	0
International equity funds	0	0
Blended equity funds	0	0
Common stock	0	0
Derivatives, net asset (liability) [Abstract]
Foreign currency contracts	(8,300,000)	19,900,000
Total financial instruments	$ 450,500,000	$ 617,400,000