Debt - Components of Debt (Parenthetical) (Details) - Senior unsecured notes [Member] € in Millions, $ in Millions	Dec. 31, 2018 USD ($)	Dec. 31, 2018 EUR (€)	Dec. 31, 2017 USD ($)	Dec. 31, 2017 EUR (€)	May 12, 2015 USD ($)
Debt Instrument [Line Items]
Long-term debt					$ 2,503
Senior Secured Tranche B-1 Euro Term Loan Due May 2022 [Member]
Debt Instrument [Line Items]
Long-term debt			$ 469	€ 394
Senior Secured Tranche B-2 Euro Term Loan Due May 2025 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 396	€ 347
6.625% Senior Notes Due May 2023 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 908		$ 1,158
Debt instrument interest rate	6.625%	6.625%	6.625%	6.625%	6.625%
7.000% Senior Notes Due May 2025 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 750		$ 750
Debt instrument interest rate	7.00%	7.00%	7.00%	7.00%
Senior Notes 6.125% Due May 2023 [Member]
Debt Instrument [Line Items]
Long-term debt			$ 350	€ 295
Debt instrument interest rate	6.125%	6.125%	6.125%	6.125%	6.125%
5.375% Senior Notes Due May 2027 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 500		$ 500
Debt instrument interest rate	5.375%	5.375%	5.375%	5.375%
4.000% Senior Notes Due May 2026 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 513	€ 450
Debt instrument interest rate	4.00%	4.00%	4.00%	4.00%