Financial Instruments - Pre-Tax Gains and Losses of Derivative and Non-Derivative Instruments Designated as Cash Flow and Net Investment Hedges (Details) - USD ($) $ in Millions	3 Months Ended
Dec. 26, 2020	Dec. 28, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) recognized in OCI – included in effectiveness assessment, cash flow hedges	$ (137)	$ 271
Gains/(Losses) reclassified from AOCI into net income – included in effectiveness assessment, cash flow hedges	311	489
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) recognized in OCI – included in effectiveness assessment, cash flow hedges	(191)	271
Gains/(Losses) reclassified from AOCI into net income – included in effectiveness assessment, cash flow hedges	314	491
Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) recognized in OCI – included in effectiveness assessment, cash flow hedges	54	0
Gains/(Losses) reclassified from AOCI into net income – included in effectiveness assessment, cash flow hedges	(3)	(2)
Foreign currency debt
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) recognized in OCI – included in effectiveness assessment, net investment hedges	$ 0	$ 24

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Amount, before tax and reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 20
-Section 45
-Paragraph 3
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Amount, before tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount, before tax and reclassification, of gain (loss) from derivative designated and qualifying as net investment hedge.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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