Stock Incentive Plans - Schedule Of Other Information Pertaining To Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions |
12 Months Ended | |||||
|---|---|---|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
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| Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | ||||||
| Weighted-average fair value of options granted (usd per share) | $ 68.60 | $ 59.94 | $ 0.00 | [1] | ||
| Total intrinsic value of stock options exercised | $ 12 | $ 19 | $ 28 | |||
| Granted (in shares) | 1 | |||||
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