Long-term debt and interest expense, net (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Long-term debt and interest expenses
Debt discount and issuance costs	$ (52)	$ (54)
Obligations under finance leases and other	5	6
Total long-term debt	2,955	2,945
Current portion of long-term debt	(29)	(30)
Non-current portion of long-term debt	2,926	2,915
Revolving credit facility
Long-term debt and interest expenses
Long-term debt	15
Term Loan B
Long-term debt and interest expenses
Long-term debt	1,955	1,960
2023 Notes
Long-term debt and interest expenses
Long-term debt	1,000	1,000
Deferred financing
Long-term debt and interest expenses
Long-term debt	$ 32	$ 33