Consolidated Balance Sheet (Parenthetical) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Consolidated Balance Sheet [Abstract]
Allowance for accounts and notes receivable	$ 11,000,000	$ 25,000,000
Accumulated depreciation, depletion and amortization	$ 66,969,000,000	$ 64,899,000,000
Common stock, shares authorized	2,500,000,000	2,500,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares issued	1,794,681,042	1,791,637,434
Treasury stock, shares	664,505,107	653,288,213