Financing (Details) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Long-term debt
Total debt	$ 3,989.2	$ 2,493.8
Less current maturities	999.9	0.1
Long-term debt	2,989.3	2,493.7
3.125% senior notes due 2016, net of unamortized discount [Member]
Long-term debt
Total debt	1,494.4	0
5.25% senior notes due 2012, net of unamortized discount [Member]
Long-term debt
Total debt	999.8	999.6
6.25% senior notes due 2014, net of unamortized discount [Member]
Long-term debt
Total debt	997.6	996.9
7.25% senior notes due 2019, net of unamortized discount [Member]
Long-term debt
Total debt	497.2	497.1
Revolving credit facility due August 13, 2013 [Member]
Long-term debt
Total debt	0	0
Revolving credit facility due August 29, 2016 [Member]
Long-term debt
Total debt	0	0
Other [Member]
Long-term debt
Total debt	$ 0.2	$ 0.2