Stock Plans (Details 3) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Stock Based Compensation Expense [Abstract] | |||
| Stock-based compensation expense | $ 252 | $ 234 | $ 290 |
| Stock Plans (Textuals) [Abstract] | |||
| Total income tax benefit recognized in the income statement for stock-based compensation arrangements | 89 | 83 | 104 |
| Restricted Stock Awards [Member] | |||
| Stock Based Compensation Expense [Abstract] | |||
| Stock-based compensation expense | 178 | 190 | 193 |
| Stock Plans (Textuals) [Abstract] | |||
| Total unrecognized compensation cost | $ 189 | ||
| Weighted-average remaining vesting period | 2 years | ||
| Stock Option [Member] | |||
| Stock Based Compensation Expense [Abstract] | |||
| Stock-based compensation expense | $ 14 | 12 | 13 |
| Stock Plans (Textuals) [Abstract] | |||
| Total unrecognized compensation cost | $ 24 | ||
| Weighted-average remaining vesting period | 2 years 1 month | ||
| Liability-Based Awards [Member] | |||
| Stock Based Compensation Expense [Abstract] | |||
| Stock-based compensation expense | $ 60 | $ 32 | $ 84 |