v3.8.0.1
Debt - Letters of Credit & Surety Bonds (Details)
€ in Millions, $ in Millions
Dec. 31, 2017
USD ($)
Dec. 31, 2017
EUR (€)
Letter of Credit    
Debt Instrument [Line Items]    
Outstanding balance $ 77  
Weighted average interest rate of outstanding borrowings 1.31% 1.31%
Ribera Salud | Letter of Credit    
Debt Instrument [Line Items]    
Letter of credit agreement $ 45 € 38
Surety Bond    
Debt Instrument [Line Items]    
Surety bonds $ 404