Share-Based Compensation Plans - Other information related to the company's share options (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
---|---|---|---|---|
Sep. 30, 2016 |
Sep. 30, 2015 |
Sep. 30, 2016 |
Sep. 30, 2015 |
|
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | ||||
Aggregate intrinsic value of stock options exercised | $ 1 | $ 3 | $ 18 | $ 103 |
Cash received from the exercise of stock options | 0 | 1 | 11 | 39 |
Tax benefit realized from the exercise of stock options | $ 1 | $ 1 | $ 5 | $ 36 |