Leases - Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease right-of-use assets	$ 4	$ 0
Finance lease assets	17
Total lease assets	21
Current finance lease liabilities	1
Operating lease liabilities	4	0
Finance lease liability	24	$ 25
Total lease liabilities	29
Finance lease, right of use asset, accumulated depreciation	$ 6