Discontinued Operations Discontinued Operations, Income Statement Disclosures - (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from discontinued operations attributable to noncontrolling interests		$ 0	$ 24	$ 47
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent		$ 0	$ 4,574	$ 987
Ireland statutory rate			12.50%	12.50%
Power Solutions
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	$ 5,200		$ 5,200
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			5,001	$ 8,000
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax			6,039	1,355
Provision for income taxes on discontinued operations			(1,441)	(321)
Income from discontinued operations attributable to noncontrolling interests			(24)	(47)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent			$ 4,574	$ 987