Debt and Credit Facilities (Long-Term Debt Excluding Current Maturities) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Long-term debt excluding current maturities	$ 3,155.1	$ 2,269.3
9.500% Senior Notes Due 2014 [Member]
Long-term debt excluding current maturities	0	655.0
5.50% Senior Notes Due 2015 [Member]
Long-term debt excluding current maturities	198.8	196.4
4.75% Senior Notes Due 2015 [Member]
Long-term debt excluding current maturities	299.7	299.7
6.875% Senior Notes Due 2018 [Member]
Long-term debt excluding current maturities	749.5	749.4
2.875% Senior notes due 2019 [Member]
Long-term debt excluding current maturities	349.5	0
9.00% Debentures Due 2021 [Member]
Long-term debt excluding current maturities	125.0	125.0
4.25% Senior notes due 2023 [Member]
Long-term debt excluding current maturities	698.7	0
7.20% Debentures Due 2014-2025 [Member]
Long-term debt excluding current maturities	82.5	90.0
6.48% Debentures Due 2025 [Member]
Long-term debt excluding current maturities	149.7	149.7
5.75% Senior notes due 2043 [Member]
Long-term debt excluding current maturities	498.0	0
Other Loans and Notes [Member]
Long-term debt excluding current maturities	$ 3.7	$ 4.1