Business Segment Information (Narrative) (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Mar. 31, 2017 |
Mar. 31, 2016 |
Mar. 31, 2017 |
Mar. 31, 2016 |
|
| Business Segment Information | ||||
| Total sales | $ 1,342 | $ 1,311 | $ 2,535 | $ 2,480 |
| Commercial Systems [Member] | ||||
| Business Segment Information | ||||
| Total sales | 594 | 611 | 1,143 | 1,173 |
| Wide Body In Flight Entertainment Products and Services [Member] | Commercial Systems [Member] | ||||
| Business Segment Information | ||||
| Total sales | $ 4 | $ 10 | $ 10 | $ 21 |