Earnings Per Share (EPS) And Dividends (Basic And Diluted Earnings Per Share Computation) (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | 0 | |
| Net Income (Loss) | $ 558 | $ 114 |
| Weighted Average Common Shares Outstanding, Basic (shares) | 504 | 505 |
| Effect of Stock Based Compensation Awards, Basic (shares) | 0 | 0 |
| Total Shares, Basic (shares) | 504 | 505 |
| Net Income, Basic (dollars per share) | $ 1.11 | $ 0.23 |
| Weighted Average Common Shares Outstanding, Diluted (shares) | 504 | 505 |
| Effect of Stock Based Compensation Awards, Diluted (shares) | 3 | 3 |
| Total Shares, Diluted (shares) | 507 | 508 |
| Net Income, Diluted (dollars per share) | $ 1.10 | $ 0.22 |