Additional Financial Statement Information - Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Paid During the Year For
Interest, Net of Amount Capitalized	$ 208	$ 270	$ 346
Income Taxes Paid, Net	76	172	121
Interest Capitalized	$ 102	$ 73	$ 49