Share-Based Compensation (Recognized Share-Based Compensation Expense) (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Recognized share-based compensation expense | $ 825 | $ 639 | $ 586 |
| Restricted share units [Member] | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Recognized share-based compensation expense | 564 | 402 | 349 |
| Stock options [Member] | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Recognized share-based compensation expense | 231 | 205 | 205 |
| Employee stock purchase plans [Member] | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Recognized share-based compensation expense | $ 30 | $ 32 | $ 32 |