Commitments, Contingencies and Other Items - Capital Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Leases, Capital
Assets acquired through capital leases	$ 2	$ 19	$ 10
Depreciation expense	14	9	5
Cash payments towards capital leases	12	8	$ 6
Assets included in property, plant and equipment	50	57
Accumulated depreciation	28	$ 24
Capital lease obligations:
2019	10
2020	6
2021	2
2022	1
2023	1
2024 and thereafter	4
Total minimum payments	24
Less: amount representing interest and executory costs	(5)
Present value of minimum payments	19
Less: current portion	(12)
Long-term portion	$ 7