Discontinued Operations Discontinued Operations, Income Statement Disclosures - (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from discontinued operations attributable to noncontrolling interests	$ 0	$ 0	$ 24
Income from Discontinued Operations, Net of Tax, Attributable to Parent	124	0	$ 4,574
Ireland statutory rate			12.50%
Power Solutions
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Consideration			$ 13,200
Disposal Group, Discontinued Operations, Consideration, net			11,600	$ 11,600
Discontinued Operation, Gain from Disposal of Discontinued Operation, before Income Tax			5,200
Discontinued Operation, Gain on Disposal of Discontinued Operation, Net of Tax			4,000
Income from Discontinued Operations, Net of Tax, Attributable to Parent	124
Depreciation and Amortization, Discontinued Operations			117
Discontinued Operations, Disposed of by Sale [Member] | Power Solutions
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales, Discontinued Operations	0	0	5,001
Discontinued Operation, Income from Discontinued Operation, before Income Tax	150	0	6,039
Provision for income taxes on discontinued operations	(26)	0	(1,441)
Income from discontinued operations attributable to noncontrolling interests	0	0	(24)
Income from Discontinued Operations, Net of Tax, Attributable to Parent	$ 124	$ 0	$ 4,574