Property, Plant and Equipment Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Millions	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Property, Plant and Equipment [Abstract]
Buildings and improvements	$ 2,445	$ 2,107
Subscriber systems	571	448
Machinery and equipment	5,572	5,137
Construction in progress	1,252	990
Land	373	367
Total property, plant and equipment	10,213	9,049
Less accumulated depreciation	(4,092)	(3,417)
Property, plant and equipment - net	$ 6,121	$ 5,632	$ 3,683