Leases - Supplemental Balance Sheet (Details) $ in Millions	Mar. 31, 2019 USD ($)
Assets
Operating leases assets	$ 117
Finance lease assets	19
Total leased assets	136
Current
Operating	32
Finance	9
Non-current
Operating	93
Finance	8
Total lease liabilities	$ 142
Weighted-average remaining lease term (years)
Operating leases	5 years 10 months
Finance leases	4 years 5 months
Weighted-average discount rate
Operating leases	6.70%
Finance leases	4.85%