Consolidated Balance Sheets Parentheticals - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Consolidated Balance Sheets Parenthetical [Abstract]
Receivables reserve	$ 8	$ 12
Less accumulated depreciation, depletion and amortization	$ (22,336)	$ (21,564)
Preferred stock, no par value	$ 0	$ 0
Preferred stock shares authorized	26,000,000	26,000,000
Preferred stock shares issued	0	0
Preferred stock shares outstanding	0	0
Common stock, par value per share	$ 1	$ 1
Common stock shares authorized	1,925,000,000	1,100,000,000
Common stock, shares issued	937,000,000	937,000,000
Common stock, held in treasury, shares	83,000,000	87,000,000