Acquisitions, Goodwill and Intangible Assets - Transaction, Integration and Financing Costs (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Transaction and integration costs	$ 27	$ 11
B/E Aerospace
Business Acquisition [Line Items]
Transaction and integration costs	17	11
Interest expense	0	3
Total Transaction, integration and financing costs	$ 17	$ 14