Discontinued Operations Discontinued Operations - Results of Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Financial Results of Discontinued Operations [Abstract]
Net sales	$ 1,037	$ 5,746	$ 6,094
Cost of sales	701	3,741	4,054
SG&A	263	1,370	1,449
Other deductions, net		321	237
Disposal Group, Including Discontinued Operation, Other Income	(473)
Earnings (Loss) before income taxes	546	314	354
Income taxes	671	269	161
Earnings (Loss), net of tax	(125)	45	193
Network Power Systems Business | Discontinued Operations, Disposed of by Sale [Member]
Financial Results of Discontinued Operations [Abstract]
Net sales	630
Cost of sales	394
SG&A	180
Disposal Group, Including Discontinued Operation, Other Income	(515)
Earnings (Loss) before income taxes	571
Income taxes	577
Earnings (Loss), net of tax	(6)
Network Power Systems Business | Discontinued Operations, Held-for-sale [Member]
Financial Results of Discontinued Operations [Abstract]
Net sales		4,378	4,426
Cost of sales		2,708	2,810
SG&A		1,101	1,143
Other deductions, net		172	222
Earnings (Loss) before income taxes		397	251
Income taxes		218	134
Earnings (Loss), net of tax		179	117
Power Generation, Motors and Drives Business | Discontinued Operations, Disposed of by Sale [Member]
Financial Results of Discontinued Operations [Abstract]
Net sales	407
Cost of sales	307
SG&A	83
Other deductions, net	42
Earnings (Loss) before income taxes	(25)
Income taxes	94
Earnings (Loss), net of tax	$ (119)
Power Generation, Motors and Drives Business | Discontinued Operations, Held-for-sale [Member]
Financial Results of Discontinued Operations [Abstract]
Net sales		1,368	1,668
Cost of sales		1,033	1,244
SG&A		269	306
Other deductions, net		149	15
Earnings (Loss) before income taxes		(83)	103
Income taxes		51	27
Earnings (Loss), net of tax		$ (134)	$ 76