XML 50 R36.htm IDEA: XBRL DOCUMENT v3.7.0.1
Long-Term Debt (Details) - USD ($)
3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Uncommitted Credit Facility [Member]    
Line of Credit Facility [Line Items]    
Borrowings Outstanding $ 0  
Commercial Paper [Member]    
Line of Credit Facility [Line Items]    
Borrowings Outstanding 0  
Average Outstanding Amount $ 0 $ 118,000,000
Weighted average interest rate (in hundredths) 0.00% 0.75%
Revolving Credit Agreement 2020 [Member]    
Line of Credit Facility [Line Items]    
Borrowings Outstanding $ 0  
Line of Credit Facility, Expiration Date Jul. 21, 2020  
Letter of Credit Facility Current Maximum Capacity $ 2,000,000,000  
Eurodollar rate at period end (in hundredths) 1.98%  
Base rate at period end (in hundredths) 4.00%  
5.875 % Senior Notes Due 2017 [Member]    
Debt Instrument [Abstract]    
Debt Instrument Issuance Face Amount $ 600,000,000  
Debt Instrument Issuance Interest Rate 5.875%