Consolidated Balance Sheets Parentheticals - USD ($) shares in Millions, $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Consolidated Balance Sheets Parenthetical [Abstract]
Less accumulated depreciation, depletion and amortization	$ (22,214)	$ (23,260)
Preferred stock, no par value	$ 0	$ 0
Preferred stock, shares authorized	26	26
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value per share	$ 1	$ 1
Common stock, shares authorized	1,100	1,100
Common stock, shares issued	937	770
Common stock, securities exchangeable no par value	$ 0	$ 0
Common stock, securities exchangeable shares authorized	29	29
Common stock, securities exchangeable shares issued	0	0
Common stock, securities exchangeable shares outstanding	0	0
Held in treasury, shares	90	93
Allowance for Doubtful Accounts Receivable, Current	$ 6	$ 4