Cash Flow Information - Schedule of Cash Paid for Interest and Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental Cash Flow Information [Abstract]
Interest, net of amount capitalized	$ 391	$ 508	$ 524
Income taxes, net of amount refunded	$ 74	$ 118	$ 324