Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
General and administrative expense [Member]
Operating lease costs	$ 15	$ 44
Amortization of leased assets	2	6
Interest Expense [Member]
Finance Lease, Interest Expense	$ 1	$ 2