Interest Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest Expense [Abstract]
Interest expense before capitalization	$ 351	$ 335	$ 358
Capitalized interest	(11)	(14)	(23)
Interest Expense	340	321	335
Interest paid, net	$ 324	$ 331	$ 314