v2.4.0.8
Fair Value Measurements (Schedule Of Carrying Values And Estimated Fair Values Of Debt Instruments) (Details) (USD $)
In Millions, unless otherwise specified
Jun. 30, 2014
Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Carrying Value $ 4,726.6 $ 4,766.4
Estimated Fair Value 5,140.6 5,096.3
4.7% Senior notes due 2021 [Member]
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Carrying Value 1,478.6 1,477.2
Estimated Fair Value 1,633.4 1,596.9
Debt instrument, interest rate, stated percentage 4.70% 4.70%
6.875% Senior notes due 2020 [Member]
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Carrying Value 1,016.6 1,024.8
Estimated Fair Value 1,090.9 1,086.7
Debt instrument, interest rate, stated percentage 6.875% 6.875%
3.25% Senior notes due 2016 [Member]
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Carrying Value 997.3 996.5
Estimated Fair Value 1,039.7 1,045.8
Debt instrument, interest rate, stated percentage 3.25% 3.25%
8.5% Senior notes due 2019 [Member]
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Carrying Value 592.2 600.5
Estimated Fair Value 637.6 635.8
Debt instrument, interest rate, stated percentage 8.50% 8.50%
7.875% Senior notes due 2040 [Member]
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Carrying Value 381.9 382.6
Estimated Fair Value 434.6 410.5
Debt instrument, interest rate, stated percentage 7.875% 7.875%
7.2% Debentures due 2027 [Member]
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Carrying Value 149.1 149.1
Estimated Fair Value 188.9 178.6
Debt instrument, interest rate, stated percentage 7.20% 7.20%
4.33% MARAD bonds, including current maturities, due 2016 [Member]
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Carrying Value 62.6 78.9
Estimated Fair Value 62.9 79.7
Debt instrument, interest rate, stated percentage 4.33% 4.33%
6.36% MARAD bonds, including current maturities, due 2015 [Member]
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Carrying Value 19.0 25.3
Estimated Fair Value 20.1 27.1
Debt instrument, interest rate, stated percentage 6.36% 6.36%
4.65% MARAD bonds, including current maturities, due 2020 [Member]
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Carrying Value 29.3 31.5
Estimated Fair Value $ 32.5 $ 35.2
Debt instrument, interest rate, stated percentage 4.65% 4.65%