Debt and Credit Facilities (Long-Term Debt Excluding Current Maturities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Long-term debt excluding current maturities	$ 3,741.7	$ 3,153.5
5.50% Senior Notes Due 2015 [Member]
Long-term debt excluding current maturities	0	198.1
4.75% Senior Notes Due 2015 [Member]
Long-term debt excluding current maturities	0	299.8
6.875% Senior Notes Due 2018 [Member]
Long-term debt excluding current maturities	749.6	749.5
2.875% Senior Notes Due 2019 [Member]
Long-term debt excluding current maturities	349.6	349.5
Two Point Six Two Five Percent Senior Notes Due Two Thousand Twenty [Member]
Long-term debt excluding current maturities	299.8	0
9.00% Debentures Due 2021 [Member]
Long-term debt excluding current maturities	125.0	125.0
4.250% Senior Notes Due 2013 [Member]
Long-term debt excluding current maturities	698.9	698.8
7.20% Debentures Due 2014-2025 [Member]
Long-term debt excluding current maturities	75.0	82.5
Three Point Five Five Percent Senior Notes due 2024 [Member]
Long-term debt excluding current maturities	497.2	0
6.48% Debentures Due 2025 [Member]
Long-term debt excluding current maturities	149.7	149.7
5.750% Senior Notes Due 2043 [Member]
Long-term debt excluding current maturities	498.0	498.0
Four Point Six Five Percent Senior Notes due Twenty Forty Four [Member]
Long-term debt excluding current maturities	298.2	0
Other Loans And Notes [Member]
Long-term debt excluding current maturities	$ 0.7	$ 2.6