Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Accumulated depreciation	$ 15,294	$ 14,736
Common stock, par value	$ 0.30	$ 0.30
Common stock, shares authorized	1,800,000,000	1,800,000,000
Common stock, shares issued	954,703,000	950,044,000
Common stock held in treasury, shares	87,041,000	87,041,000