Financial Instruments - Pre-Tax Gains and Losses of Derivative and Non-Derivative Instruments Designated as Hedges (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 28, 2019	Sep. 29, 2018	Sep. 30, 2017
Cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) recognized in OCI – effective portion	$ (959)	$ 683	$ 1,804
Gains/(Losses) reclassified from AOCI into net income – effective portion	(123)	(481)	1,956
Cash flow hedges \| Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) recognized in OCI – effective portion	(959)	682	1,797
Gains/(Losses) reclassified from AOCI into net income – effective portion	(116)	(482)	1,958
Cash flow hedges \| Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) recognized in OCI – effective portion	0	1	7
Gains/(Losses) reclassified from AOCI into net income – effective portion	(7)	1	(2)
Net investment hedges \| Foreign currency debt
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) recognized in OCI – effective portion	(58)	4	67
Fair value hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) on derivative instruments designated as fair value hedges	3,088	(1,531)	(810)
Gains/(Losses) related to hedged items in fair value hedges	(3,086)	1,530	810
Fair value hedges \| Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) on derivative instruments designated as fair value hedges	1,020	(168)	0
Gains/(Losses) related to hedged items in fair value hedges	(1,018)	167	0
Fair value hedges \| Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) on derivative instruments designated as fair value hedges	2,068	(1,363)	(810)
Gains/(Losses) related to hedged items in fair value hedges	$ (2,068)	$ 1,363	$ 810

Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
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- Definition

Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
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- Definition

Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
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