Discontinued Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Financial Results of Discontinued Operations [Abstract]
Income taxes		$ 269	$ 161	$ 211
Earnings (Loss), net of tax		45	193	(54)
Cash provided by operating activities and used in investing activities for discontinued operations [Abstract]
Cash provided by operating activities		382	489	693
Cash used in investing activities		(77)	(88)	(106)
Discontinued Operations, Held-for-sale [Member]
Discontinued Operations Disclosures
Separation costs		220	52
Separation costs, income tax expense		143	42
Separation costs, legal, consulting, investment banking and other costs		77	10
Benefit from ceasing depreciation and amortization on assets for discontinued businesses held-for-sale		24
Goodwill impairment				508
Cash payments for separation costs		179
Financial Results of Discontinued Operations [Abstract]
Net sales		5,746	6,094	6,842
Cost of sales		3,741	4,054	4,446
SG&A		1,370	1,449	1,551
Other deductions, net		321	237	688
Earnings (Loss) before income taxes		314	354	157
Income taxes		269	161	211
Earnings (Loss), net of tax		45	193	(54)
Cash provided by operating activities and used in investing activities for discontinued operations [Abstract]
Cash provided by operating activities		382	489	693
Cash used in investing activities		(77)	(88)	(106)
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Receivables, less allowances		1,492	1,449
Inventories		578	582
Other current assets		130	105
Property plant & equipment, net		611	656
Goodwill		2,691	2,806
Other noncurrent assets		528	624
Total assets held-for-sale		6,030	6,222	6,904
Accounts payable		840	821
Other current liabilities		761	745
Deferred taxes and other noncurrent liabilities		326	332
Total liabilities held-for-sale		1,927	1,898
Network Power Systems Business [Member] | Discontinued Operations, Held-for-sale [Member]
Discontinued Operations Disclosures
Agreed-upon purchase price of business		4,000
Financial Results of Discontinued Operations [Abstract]
Net sales		4,378	4,426	4,868
Cost of sales		2,708	2,810	3,012
SG&A		1,101	1,143	1,205
Other deductions, net		172	222	668
Earnings (Loss) before income taxes		397	251	(17)
Income taxes		218	134	163
Earnings (Loss), net of tax		179	117	(180)
Cash provided by operating activities and used in investing activities for discontinued operations [Abstract]
Cash provided by operating activities		343	378	507
Cash used in investing activities		(33)	(48)	(57)
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Receivables, less allowances		1,202	1,121
Inventories		381	386
Other current assets		108	90
Property plant & equipment, net		352	362
Goodwill		2,111	2,144
Other noncurrent assets		473	557
Total assets held-for-sale		4,627	4,660
Accounts payable		664	611
Other current liabilities		620	599
Deferred taxes and other noncurrent liabilities		227	245
Total liabilities held-for-sale		1,511	1,455
Power Generation, Motors and Drives Businesses [Member] | Discontinued Operations, Held-for-sale [Member]
Discontinued Operations Disclosures
Agreed-upon purchase price of business		1,200
Loss on write down of assets		103
Financial Results of Discontinued Operations [Abstract]
Net sales		1,368	1,668	1,974
Cost of sales		1,033	1,244	1,434
SG&A		269	306	346
Other deductions, net		149	15	20
Earnings (Loss) before income taxes		(83)	103	174
Income taxes		51	27	48
Earnings (Loss), net of tax		(134)	76	126
Cash provided by operating activities and used in investing activities for discontinued operations [Abstract]
Cash provided by operating activities		39	111	186
Cash used in investing activities		(44)	(40)	$ (49)
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Receivables, less allowances		290	328
Inventories		197	196
Other current assets		22	15
Property plant & equipment, net		259	294
Goodwill		580	662
Other noncurrent assets		55	67
Total assets held-for-sale		1,403	1,562
Accounts payable		176	210
Other current liabilities		141	146
Deferred taxes and other noncurrent liabilities		99	87
Total liabilities held-for-sale		$ 416	$ 443
Scenario, Forecast [Member] | Discontinued Operations, Disposed of by Sale [Member]
Discontinued Operations Disclosures
Potential U.S. tax costs due to repatriation of cash related to discontinued operations	$ 200
Estimated sales proceeds to be received offshore	1,500
Scenario, Forecast [Member] | Discontinued Operations, Held-for-sale [Member]
Discontinued Operations Disclosures
Disposal gain (loss), pretax	500
Disposal gain (loss), after-tax	$ 0