Debt (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	$ 2,078.0	$ 2,076.2
Current maturities	(32.3)	(29.2)
Long-term maturities	2,045.7	2,047.0
Senior Notes Payable Due 2014 [Member]
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	250.0	250.0
Maturity date	Jun. 02, 2014
Senior Notes Payable Due 2015 [Member]
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	250.0	250.0
Maturity date	Apr. 30, 2015
Interest rate (in hundredths)	1.60%	1.60%
Senior Notes Payable Due 2018 [Member]
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	450.0	450.0
Maturity date	Jul. 15, 2018
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
Maturity date	Jun. 01, 2021
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	250.0
Maturity date	Apr. 30, 2022
Interest rate (in hundredths)	3.60%	3.60%
Senior Notes Payable Due 2038 [Member]
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	300.0	300.0
Maturity date	Jul. 15, 2038
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
Maturity date	Jun. 01, 2041
Interest rate (in hundredths)	5.95%	5.95%
Senior Notes Payable [Member]
Debt Instrument [Line Items]
Unamortized original issue discount	(4.0)	(4.1)
Other Debt [Member]
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	20.9	19.6
Obligations Under Capital Leases [Member]
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	61.1	60.7
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	187.8
Maximum borrowing capacity	250.0
Remaining capacity under revolving line of credit facility	$ 62.2