Summary Of Significant Accounting Policies (Details) - USD ($)	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Oct. 01, 2019	Oct. 01, 2018	Sep. 30, 2018
Summary Of Accounting Policies [Line Items]
Retained earnings	$ 24,955,000,000	$ 24,199,000,000
Finished products	584,000,000	578,000,000
Raw materials and work in process	1,344,000,000	1,302,000,000
Total inventories	1,928,000,000	1,880,000,000
Land	350,000,000	336,000,000
Buildings	2,335,000,000	2,219,000,000
Machinery and equipment	5,907,000,000	5,645,000,000
Construction in progress	463,000,000	471,000,000
Property, plant and equipment, at cost	9,055,000,000	8,671,000,000
Less: Accumulated depreciation	5,367,000,000	5,029,000,000
Property, plant and equipment, net	$ 3,688,000,000	3,642,000,000
Percentage of revenue from multiple deliverable arrangements	5.00%
Collateral balance posted	$ 0
Collateral held from counterparties	0
Undistributed earnings of non-U.S. subsidiaries	$ 4,600,000,000
Minimum [Member]
Summary Of Accounting Policies [Line Items]
Warranty period (in years)	1 year
Maximum [Member]
Summary Of Accounting Policies [Line Items]
Warranty period (in years)	2 years
Percentage Of Sales On Product Warranty Expense	1.00%
Percentage of revenue from percentage-of-completion accounting method	5.00%
General duration of hedge positions is equal to or less than (in years)	2 years
Building [Member] | Minimum [Member]
Summary Of Accounting Policies [Line Items]
Property, plant and equipment, useful life	30 years
Building [Member] | Maximum [Member]
Summary Of Accounting Policies [Line Items]
Property, plant and equipment, useful life	40 years
Machinery and Equipment [Member] | Minimum [Member]
Summary Of Accounting Policies [Line Items]
Property, plant and equipment, useful life	8 years
Machinery and Equipment [Member] | Maximum [Member]
Summary Of Accounting Policies [Line Items]
Property, plant and equipment, useful life	12 years
Retained earnings
Summary Of Accounting Policies [Line Items]
Adoption of accounting standard updates	$ 0	30,000,000			$ 103,000,000
Accounting Standards Update 2017-07 [Member]
Summary Of Accounting Policies [Line Items]
Effect of change in accounting principal on operating results, retirement benefits		40,000,000
Accounting Standards Update 2016-16 [Member] | Retained earnings
Summary Of Accounting Policies [Line Items]
Adoption of accounting standard updates		3,000,000
Accounting Standards Update 2016-02 [Member]
Summary Of Accounting Policies [Line Items]
Operating lease right-of-use assets			$ 500,000,000
Total lease liabilities			$ 500,000,000
Accounting standards update 2018-02, early adoption [Member] | Reclassification out of accumulated other comprehensive income [Member] | Retained earnings
Summary Of Accounting Policies [Line Items]
Adoption of accounting standard updates		$ 100,000,000
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Summary Of Accounting Policies [Line Items]
Retained earnings				$ 30,000,000