Other Assets (Narrative) (Details) $ in Millions |
3 Months Ended | 6 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|---|
|
Mar. 31, 2017
USD ($)
Joint_Venture
|
Mar. 31, 2016
USD ($)
|
Mar. 31, 2017
USD ($)
Joint_Venture
|
Mar. 31, 2016
USD ($)
|
Sep. 30, 2016
USD ($)
|
|
| Other Assets [Abstract] | |||||
| Number of equity affiliates (joint ventures) | Joint_Venture | 7 | 7 | |||
| Ownership Percentage | 50.00% | 50.00% | |||
| Sales to equity affiliates | $ 69 | $ 55 | $ 136 | $ 101 | |
| Deferred profit generated from sales to equity affiliates | $ 4 | $ 2 | |||
| Exchange and rental assets estimated useful life | 15 years | ||||
| Depreciation expense, exchange and rental assets | $ 3 | $ 3 | $ 5 | $ 5 | |