v3.10.0.1
Share-Based Compensation (Recognized Share-Based Compensation Expense) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Recognized share-based compensation expense $ 639 $ 586 $ 507
Restricted share units [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Recognized share-based compensation expense 402 349 306
Stock options [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Recognized share-based compensation expense 205 205 173
Employee stock purchase plans [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Recognized share-based compensation expense $ 32 $ 32 $ 28