Discontinued Operations - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Discontinued Operations Disclosures
Earnings (Loss), net of tax	$ 0	$ (125)	$ 45
Diluted earnings from discontinued operations per common share	$ 0.00	$ (0.19)	$ 0.07
Discontinued Operations, Disposed of by Sale [Member]
Discontinued Operations Disclosures
Payments for income taxes and repatriation costs, discontinued operations cash flow		$ 700
Discontinued Operations, Held-for-sale [Member]
Discontinued Operations Disclosures
Cash payments for separation costs			$ 179
Combined, Network Power and Power Generation, motors and Drives Business [Member] | Discontinued Operations, Disposed of by Sale [Member]
Discontinued Operations Disclosures
Income tax expense for repatriation of sales proceeds and cash from discontinued operations		109
Benefit from ceasing depreciation and amortization on assets for discontinued businesses held-for-sale		32
Combined, Network Power and Power Generation, motors and Drives Business [Member] | Discontinued Operations, Held-for-sale [Member]
Discontinued Operations Disclosures
Benefit from ceasing depreciation and amortization on assets for discontinued businesses held-for-sale			24
Earnings (Loss) from discontinued operations			344
After-tax separation costs related to strategic portfolio repositioning actions			299
Separation Costs, Income Tax Expense			143
Separation Costs, Fees			77
Network Power Systems Business | Discontinued Operations, Disposed of by Sale [Member]
Discontinued Operations Disclosures
Agreed-upon purchase price of business		4,000
Earnings (Loss), net of tax		(6)
After tax gain on completion of sale of business		125
Disposal gain (loss), pretax		519
Network Power Systems Business | Discontinued Operations, Held-for-sale [Member]
Discontinued Operations Disclosures
Earnings (Loss), net of tax			179
Power Generation, Motors and Drives Business | Discontinued Operations, Disposed of by Sale [Member]
Discontinued Operations Disclosures
Agreed-upon purchase price of business		1,200
Earnings (Loss), net of tax		(119)
Disposal gain (loss), pretax		(36)
After tax loss on completion of sale of business		$ 173
Power Generation, Motors and Drives Business | Discontinued Operations, Held-for-sale [Member]
Discontinued Operations Disclosures
Earnings (Loss), net of tax			(134)
Loss on write down of assets			$ 103