Business Segment Information - Summary of Sales by Product Category (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Business Segment Information
Sales	$ 2,011	$ 1,193
Interior Systems
Business Segment Information
Sales	656	0
Interior Systems | Interior products and services
Business Segment Information
Sales	356	0
Interior Systems | Aircraft seating
Business Segment Information
Sales	300	0
Commercial Systems
Business Segment Information
Sales	608	549
Commercial Systems | Air transport aviation electronics
Business Segment Information
Sales	380	329
Commercial Systems | Wide-body in-flight entertainment products and services
Business Segment Information
Sales	4	6
Commercial Systems | Business and regional aviation electronics
Business Segment Information
Sales	228	220
Government Systems
Business Segment Information
Sales	573	475
Government Systems | Avionics
Business Segment Information
Sales	333	319
Government Systems | Communication and navigation
Business Segment Information
Sales	240	156
Information Management Services
Business Segment Information
Sales	$ 174	$ 169