Debt (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	May 17, 2012	Dec. 31, 2011
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	$ 2,047.8		$ 1,584.8
Current maturities	(30.0)		(10.6)
Long-term maturities	2,017.8		1,574.2
Issuance date of unsecured senior notes	May 17, 2012
Principal amount of senior unsecured notes		500.0
Date of first interest payment on unsecured senior notes	Oct. 30, 2012
Senior Notes Payable Due 2014 [Member]
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	250.0		250.0
Senior Notes Payable Due 2015 [Member]
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	250.0		0
Interest rate (in hundredths)	1.60%		1.60%
Percentage of principal amount under a change of control repurchase event (in hundredths)	99.957%
Senior Notes Payable Due 2018 [Member]
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	450.0		450.0
Interest rate (in hundredths)	6.375%		6.375%
Senior Notes Payable Due 2021 [Member]
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	250.0		250.0
Interest rate (in hundredths)	4.50%		4.50%
Senior Notes Payable Due 2022 [Member]
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	250.0		0
Interest rate (in hundredths)	3.60%		3.60%
Percentage of principal amount under a change of control repurchase event (in hundredths)	99.744%
Senior Notes Payable Due 2038 [Member]
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	300.0		300.0
Interest rate (in hundredths)	7.00%		7.00%
Senior Notes Payable Due 2041 [Member]
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	250.0		250.0
Interest rate (in hundredths)	5.95%		5.95%
Other Long Term Debt [Member]
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	23.7		70.0
Obligations Under Capital Leases [Member]
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	28.4		18.6
Senior Notes Payable [Member]
Debt Instrument [Line Items]
Unamortized original issue discount	(4.3)		(3.8)
Amended Line of Credit [Member]
Debt Instrument [Line Items]
Letters of credit outstanding	25.4
Maximum borrowing capacity	835.0
Remaining capacity under revolving line of credit facility	809.6
Line of Credit Multi Currency [Member]
Debt Instrument [Line Items]
Letters of credit outstanding	193.1
Maximum borrowing capacity	250.0
Remaining capacity under revolving line of credit facility	$ 56.9