Interest Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Interest Expense [Abstract]
Interest on borrowings(1)	$ 46	$ 57	$ 139	$ 171
Fees on financing agreements(1)	2	4	6	10
Interest on tax liabilities(2)	0	3	(4)	3
Interest Costs Capitalized	0	(1)	0	(2)
Interest expense	$ 48	$ 63	$ 141	$ 182