Long-term debt and interest expense, net (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Long-term debt and interest expenses
Debt discount and issuance costs	$ (63)	$ (54)
Obligations under finance leases and other	5	6
Total long-term debt	2,416	2,945
Current portion of long-term debt	(9)	(30)
Non-current portion of long-term debt	2,407	2,915
Term Loan B
Long-term debt and interest expenses
Long-term debt	1,444	1,960
2023 Notes
Long-term debt and interest expenses
Long-term debt	850	1,000
2027 Notes
Long-term debt and interest expenses
Long-term debt	150
Deferred financing
Long-term debt and interest expenses
Long-term debt	$ 30	$ 33