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Derivative Instruments - Narrative (Details)
MMBTU in Millions
3 Months Ended
Mar. 31, 2018
USD ($)
MMBTU
Mar. 31, 2017
USD ($)
Derivative Instruments, Gain (Loss) [Line Items]    
Typical hedging period 5 years  
Net liability aggregate fair value $ 15,000,000  
Collateral provided to counterparties related to derivatives $ 14,000,000  
Cash flow hedging | Commodity contracts    
Derivative Instruments, Gain (Loss) [Line Items]    
Notional amount of commodity instruments (in mmbtu) | MMBTU 40  
Loss on cash flow hedge ineffectiveness $ 0 $ 0
Cash flow hedging | Foreign exchange contracts    
Derivative Instruments, Gain (Loss) [Line Items]    
Loss on cash flow hedge ineffectiveness 0 $ 0
Purchases of products and services | Cash flow hedging | Foreign exchange contracts    
Derivative Instruments, Gain (Loss) [Line Items]    
Notional amounts of foreign exchange forward contracts 107,000,000  
Intercompany loan | Cash flow hedging | Foreign exchange contracts    
Derivative Instruments, Gain (Loss) [Line Items]    
Notional amounts of foreign exchange forward contracts $ 16,000,000