Property, Plant And Equipment (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Interest capitalized	$ 81	$ 83	$ 81
Property, plant and equipment included in accounts payable	182	256
Property, plant and equipment additions, non-cash	47	128
Property, Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciation	$ 1,533	$ 1,567	$ 1,556