XML 78 R54.htm IDEA: XBRL DOCUMENT v3.8.0.1
Debt and Credit Facilities (Narrative) (Details) - USD ($)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Jan. 31, 2017
Line of Credit Facility [Line Items]        
Commercial Paper $ 0 $ 200,000,000    
Interest expense, debt $ 247,000,000 $ 228,000,000 $ 108,000,000  
Senior Unsecured Notes 1.800% due 2019        
Line of Credit Facility [Line Items]        
Unsecured Debt       $ 500,000,000
Stated interest rate       1.80%
Commercial Paper        
Line of Credit Facility [Line Items]        
Maturities of time deposits 397 days      
Commercial Paper | Maximum        
Line of Credit Facility [Line Items]        
Commercial paper $ 1,500,000,000