Fair Value Measurements and Derivatives - Summary of Fixed-to-Fixed Cross-Currency Swaps (Details)
€ in Millions, $ in Millions
Mar. 31, 2018
USD ($)
Mar. 31, 2018
EUR (€)
Dec. 31, 2017
USD ($)
Dec. 31, 2017
EUR (€)
Apr. 04, 2017
Dec. 31, 2016
USD ($)
Senior Notes Due June 2026 [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Interest rate [1] 6.50% 6.50% 6.50% 6.50%    
Senior Notes Due April 2025 [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Interest rate 5.75% [1] 5.75% [1] 5.75% [1] 5.75% [1] 5.75%  
Cash Flow Hedging [Member] | Senior Notes Due June 2026 [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, amount of hedged item $ 375         $ 375
Interest rate 6.50% 6.50%        
Derivative, fixed interest rate 5.14% 5.14%        
Cash Flow Hedging [Member] | Senior Notes Due April 2025 [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, amount of hedged item $ 400   $ 400      
Interest rate 5.75% 5.75%        
Derivative, fixed interest rate 3.85% 3.85%        
Cash Flow Hedging [Member] | Intercompany Notes [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, amount of hedged item | €   € 281   € 281    
Interest rate 3.91% 3.91%        
Currency Swap [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, Notional Amount $ 1,121   $ 1,112      
Currency Swap [Member] | United States of America, Dollars [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, Notional Amount 346          
Currency Swap [Member] | Euro Member Countries, Euro [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, Notional Amount 775          
Currency Swap [Member] | Cash Flow Hedging [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, Notional Amount 1,121          
Currency Swap [Member] | Cash Flow Hedging [Member] | United States of America, Dollars [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, Notional Amount 346          
Currency Swap [Member] | Cash Flow Hedging [Member] | Euro Member Countries, Euro [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, Notional Amount 775          
Currency Swap [Member] | Cash Flow Hedging [Member] | Senior Notes Due June 2026 [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, Notional Amount $ 375 € 338        
Currency Swap [Member] | Cash Flow Hedging [Member] | Senior Notes Due June 2026 [Member] | United States of America, Dollars [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, fixed interest rate 6.50% 6.50%        
Currency Swap [Member] | Cash Flow Hedging [Member] | Senior Notes Due June 2026 [Member] | Euro Member Countries, Euro [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, fixed interest rate 5.14% 5.14%        
Currency Swap [Member] | Cash Flow Hedging [Member] | Senior Notes Due April 2025 [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, Notional Amount $ 400 € 371        
Derivative, fixed interest rate 3.85% 3.85%        
Currency Swap [Member] | Cash Flow Hedging [Member] | Senior Notes Due April 2025 [Member] | United States of America, Dollars [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, fixed interest rate 5.75% 5.75%        
Currency Swap [Member] | Cash Flow Hedging [Member] | Senior Notes Due April 2025 [Member] | Euro Member Countries, Euro [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, fixed interest rate 3.85% 3.85%        
Currency Swap [Member] | Cash Flow Hedging [Member] | Intercompany Notes [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, Notional Amount $ 300 € 281        
Currency Swap [Member] | Cash Flow Hedging [Member] | Intercompany Notes [Member] | United States of America, Dollars [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, fixed interest rate 6.00% 6.00%        
Currency Swap [Member] | Cash Flow Hedging [Member] | Intercompany Notes [Member] | Euro Member Countries, Euro [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative, fixed interest rate 3.91% 3.91%        
[1] In conjunction with the issuance of the April 2025 Notes we entered into 8-year fixed-to-fixed cross-currency swaps which have the effect of economically converting the April 2025 Notes to euro-denominated debt at a fixed rate of 3.850%. In conjunction with the issuance of the June 2026 Notes we entered into 10-year fixed-to-fixed cross-currency swaps which have the effect of economically converting the June 2026 Notes to euro-denominated debt at a fixed rate of 5.140%. See Note 14 for additional information.