Property, Plant and Equipment, Net of Accumulated Depreciation (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment, Net of Accumulated Depreciation [Abstract]
Interest costs capitalized	$ 49	$ 36	$ 23
Precious metals	3,000	3,000
Depletion	$ 14	$ 13	$ 20