Debt (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2012 Senior Notes Payable Due 2014 [Member]	Dec. 31, 2011 Senior Notes Payable Due 2014 [Member]	Mar. 31, 2012 Senior Notes Payable Due 2018 [Member]	Dec. 31, 2011 Senior Notes Payable Due 2018 [Member]	Mar. 31, 2012 Senior Notes Payable Due 2021 [Member]	Dec. 31, 2011 Senior Notes Payable Due 2021 [Member]	Mar. 31, 2012 Senior Notes Payable Due 2038 [Member]	Dec. 31, 2011 Senior Notes Payable Due 2038 [Member]	Mar. 31, 2012 Senior Notes Payable Due 2041 [Member]	Dec. 31, 2011 Senior Notes Payable Due 2041 [Member]	Mar. 31, 2012 Other Long Term Debt [Member]	Dec. 31, 2011 Other Long Term Debt [Member]	Mar. 31, 2012 Obligations Under Capital Leases [Member]	Dec. 31, 2011 Obligations Under Capital Leases [Member]	Mar. 31, 2012 Senior Notes Payable [Member]	Mar. 31, 2011 Senior Notes Payable [Member]	Mar. 31, 2012 Amended Line of Credit [Member]	Mar. 31, 2012 Line of Credit Multi Currency [Member]
Debt Instrument [Line Items]
Principal outstanding, net of unamortized discount	$ 1,607.7	$ 1,584.8	$ 250.0	$ 250.0	$ 450.0	$ 450.0	$ 250.0	$ 250.0	$ 300.0	$ 300.0	$ 250.0	$ 250.0	$ 89.2	$ 70.0	$ 22.3	$ 18.6
Unamortized original issue discount																	(3.8)	(3.8)
Current maturities	(33.1)	(10.6)
Long-term maturities	1,574.6	1,574.2
Interest rate (in hundredths)					6.375%	6.375%	4.50%	4.50%	7.00%	7.00%	5.95%	5.95%
Letters of credit outstanding																			25.4	114.0
Maximum borrowing capacity																			835.0	250.0
Remaining capacity under revolving line of credit facility																			$ 809.6	$ 136.0