Leases - Supplemental lease balance sheet information (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 10, 2019
Leases
Non-current operating lease assets	$ 176	$ 63
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Non-current operating lease assets
Finance	$ 5
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Property, Plant and Equipment, Net.
Total leased assets	$ 181
Current operating lease liabilities	$ 40
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Current operating lease liabilities
Operating lease liability, non current	$ 173
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Operating lease liability, non current
Finance lease liability, current	$ 2
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other Liabilities, Current
Finance lease liability, non current	$ 1
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other Liabilities, Noncurrent
Total leased Liabilities	$ 216