Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) shares in Millions, $ in Millions |
Sep. 30, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Current assets: | ||
| Allowance for bad debts | $ 165 | $ 175 |
| Accumulated depreciation | $ 11,911 | $ 11,198 |
| Shareholders' equity: | ||
| Common stock, par value (in dollars per share) | $ 2.50 | $ 2.50 |
| Common stock, shares authorized (in shares) | 2,000 | 2,000 |
| Common stock, shares issued (in shares) | 1,069 | 1,070 |
| Treasury shares (in shares) | 197 | 204 |