Stock-Based Compensation and Earnings Per Share (Stock-Based Compensation Expense) (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Mar. 31, 2016 |
Mar. 31, 2015 |
Mar. 31, 2016 |
Mar. 31, 2015 |
|
| Stock-Based Compensation | ||||
| Stock-based compensation expense | $ 9 | $ 7 | $ 15 | $ 12 |
| Income tax benefit | 3 | 2 | 5 | 4 |
| Employee Share Based Compensation Allocation Of Recognized Expense Cost Of Sales [Member] | ||||
| Stock-Based Compensation | ||||
| Stock-based compensation expense | 3 | 2 | 5 | 4 |
| Employee Service Share Based Compensation Allocation Of Recognized Expense Selling General and Administrative [Member] | ||||
| Stock-Based Compensation | ||||
| Stock-based compensation expense | $ 6 | $ 5 | $ 10 | $ 8 |