Fair Value Measurements and Derivatives - Summary of Fixed-to-Fixed Cross-Currency Swaps (Details) € in Millions, $ in Millions		Sep. 30, 2019 USD ($)	Sep. 30, 2019 EUR (€)	Dec. 31, 2018 USD ($)
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%
Senior Notes Due April 2025 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate	[1]	5.75%	5.75%	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
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
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
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		$ 1,081		$ 1,097
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		306
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		1,081
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		306
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
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 15 for additional information.