Income Taxes (Unrecognized Tax Benefit Changes) (Details) $ in Millions |
Sep. 30, 2016
USD ($)
|
|---|---|
| Minimum [Member] | |
| Significant Change In Unrecognized Tax Benefits Is Reasonably Possible [Line Items] | |
| Decrease in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change | $ 100 |
| Maximum [Member] | |
| Significant Change In Unrecognized Tax Benefits Is Reasonably Possible [Line Items] | |
| Decrease in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change | $ 685 |