XML 58 R47.htm IDEA: XBRL DOCUMENT v3.10.0.1
Long-Term Debt and Commercial Paper (Narrative) (Details) - USD ($)
6 Months Ended 12 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Dec. 31, 2017
Debt Instrument [Line Items]      
Repayment of 6.75% Senior Debt $ 400,000,000 $ 0  
Letters of credit, amount outstanding 47,400,000    
Commercial paper, maximum aggregate amount outstanding permitted 1,000,000,000    
Commercial paper, amount outstanding $ 690,000,000   $ 330,000,000
Commercial Paper [Member]      
Debt Instrument [Line Items]      
Weighted-average annual interest rate 2.64%   1.97%
Maximum [Member] | Commercial Paper [Member]      
Debt Instrument [Line Items]      
Maturity period of debt 397 days    
Weighted Average [Member] | Commercial Paper [Member]      
Debt Instrument [Line Items]      
Maturity period of debt 9 days   24 days
3.35% Senior Notes due 2021 [Member] | Senior Notes [Member]      
Debt Instrument [Line Items]      
Senior notes $ 300,000,000   $ 300,000,000
Debt instrument, maturity date Jan. 15, 2021    
Percentage interest on debt instrument 3.35%    
3.5% Senior Notes Due 2024 [Member] | Senior Notes [Member]      
Debt Instrument [Line Items]      
Senior notes $ 450,000,000   450,000,000
Debt instrument, maturity date Nov. 15, 2024    
Percentage interest on debt instrument 3.50%    
4.5% Senior Notes due 2025 [Member] | Senior Notes [Member]      
Debt Instrument [Line Items]      
Senior notes $ 450,000,000   450,000,000
Debt instrument, maturity date Oct. 01, 2025    
Percentage interest on debt instrument 4.50%    
3.8% Senior Notes Due 2027 [Member] | Senior Notes [Member]      
Debt Instrument [Line Items]      
Senior notes $ 300,000,000   300,000,000
Debt instrument, maturity date Nov. 15, 2027    
Percentage interest on debt instrument 3.80%    
6.75% Senior Notes Due 2018 [Member] | Senior Notes [Member]      
Debt Instrument [Line Items]      
Senior notes $ 0   400,000,000
Debt instrument, maturity date Apr. 15, 2018    
Percentage interest on debt instrument 6.75%    
Repayment of 6.75% Senior Debt $ 400,000,000    
5.5% Senior Notes Due 2020 [Member] | Senior Notes [Member]      
Debt Instrument [Line Items]      
Senior notes $ 350,000,000   350,000,000
Debt instrument, maturity date Feb. 01, 2020    
Percentage interest on debt instrument 5.50%    
Revolving Credit Facility Due 2022 [Member]      
Debt Instrument [Line Items]      
Maximum borrowing capacity under revolving credit facility $ 1,800,000,000    
Additional borrowing capacity under accordion feature of revolving credit facility 500,000,000    
Revolving credit facility, amount outstanding 0   0
Revolving credit facilities letter of credit sublimit 200,000,000    
Additional borrowing capacity under the revolving credit facility 1,800,000,000    
Borrowing capacity limited under the maximum consolidated leverage ratio $ 1,100,000,000    
Leverage ratio, minimum threshold, current credit spread 2.0    
Leverage ratio, maximum threshold, current credit spread 3.25    
Leverage ratio, minimum threshold, increase in credit spread 3.25    
Impact on credit spread from increase in leverage ratio 0.125%    
Revolving Credit Facility Due 2022 [Member] | Minimum [Member]      
Debt Instrument [Line Items]      
Commitment fee on undrawn amounts (percent) 0.15%    
Revolving Credit Facility Due 2022 [Member] | Maximum [Member]      
Debt Instrument [Line Items]      
Commitment fee on undrawn amounts (percent) 0.25%    
Revolving Credit Facility Due 2022 [Member] | Line of Credit [Member]      
Debt Instrument [Line Items]      
Debt instrument, maturity date Oct. 19, 2022    
Revolving Credit Facility Due 2022 [Member] | Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]      
Debt Instrument [Line Items]      
Basis spread on variable interest rates (percent) 1.25%    
Revolving Credit Facility Due 2022 [Member] | Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]      
Debt Instrument [Line Items]      
Basis spread on variable interest rates (percent) 1.625%    
Revolving Credit Facility Due 2022 [Member] | Line of Credit [Member] | Base Rate [Member] | Minimum [Member]      
Debt Instrument [Line Items]      
Basis spread on variable interest rates (percent) 0.25%    
Revolving Credit Facility Due 2022 [Member] | Line of Credit [Member] | Base Rate [Member] | Maximum [Member]      
Debt Instrument [Line Items]      
Basis spread on variable interest rates (percent) 0.625%    
Capital Leases and Other Debt [Member]      
Debt Instrument [Line Items]      
Capital leases and other debt $ 133,900,000   $ 139,400,000