Debt and Credit Facilities (Long-Term Debt Excluding Current Maturities) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Long-term debt excluding current maturities	$ 2,879.3	$ 2,879.3
6.000% Senior Notes Due 2013 [Member]
Long-term debt excluding current maturities	599.9	599.9
9.500% Senior Notes Due 2014 [Member]
Long-term debt excluding current maturities	655.0	655.0
5.50% Senior Notes Due 2015 [Member]
Long-term debt excluding current maturities	199.8	199.8
4.75% Senior Notes Due 2015 [Member]
Long-term debt excluding current maturities	299.6	299.6
6.875% Senior Notes Due 2018 [Member]
Long-term debt excluding current maturities	749.3	749.3
9.00% Debentures Due 2021 [Member]
Long-term debt excluding current maturities	125.0	125.0
7.20% Debentures Due 2013-2025 [Member]
Long-term debt excluding current maturities	97.5	97.5
6.48% Debentures Due 2025 [Member]
Long-term debt excluding current maturities	149.7	149.7
Other Loans and Notes [Member]
Long-term debt excluding current maturities	$ 3.5	$ 3.5