v2.4.0.8
Debt (Narrative) (Details) (USD $)
 12 Months Ended 12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2013
Senior Notes [Member]
5.15% Notes Due 2043 [Member]
Dec. 31, 2013
Revolving Credit Facility [Member]
Sep. 30, 2013
Revolving Credit Facility [Member]
Dec. 31, 2013
Revolving Credit Facility [Member]
Maximum [Member]
Dec. 31, 2013
Revolving Credit Facility [Member]
Minimum [Member]
Debt Instrument [Line Items]                
Debt Instrument, Face Amount $ 2,700,000,000.0 $ 2,400,000,000.0   $ 300,000,000        
Debt Instrument, Interest Rate, Stated Percentage       5.15%        
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months 250,000,000              
Long-term Debt, Maturities, Repayments of Principal in Year Two 0              
Long-term Debt, Maturities, Repayments of Principal in Year Three 250,000,000              
Long-term Debt, Maturities, Repayments of Principal in Year Four 0              
Long-term Debt, Maturities, Repayments of Principal in Year Five 250,000,000              
Long-term Debt, Maturities, Repayments of Principal after Year Five 1,900,000,000              
Notes At Price       99.60%        
After Underwriting Discounts       295,600,000        
Payments of Debt Issuance Costs 4,849,000 2,552,000 4,575,000 3,100,000 1,700,000      
Write off of Deferred Debt Issuance Cost         200,000      
Line of Credit Facility, Maximum Borrowing Capacity         1,000,000,000.0 800,000,000.0    
Debt Instrument, Basis Spread on Variable Rate         1.125%   1.75% 1.00%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage         0.125%   0.28% 0.10%
Letters of Credit Outstanding, Amount         5,600,000      
Debt Instrument, Covenant Description         The revolving credit facility described above requires us to maintain a specified ratio of consolidated debt to EBITDA (as defined in the agreement) of no greater than 5.0 to 1.0      
Debt Instrument, Consolidated Debt to EBITDA Ratio         5.0      
Cash Payments for Interest $ 134,600,000 $ 123,300,000 $ 111,700,000