Financial Instruments - Pre-Tax Gains and Losses of Derivative and Non-Derivative Instruments Designated as Hedges (Details) - USD ($) $ in Millions	3 Months Ended
Dec. 29, 2018	Dec. 30, 2017
Cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) recognized in OCI – effective portion	$ (478)	$ 154
Gains/(Losses) reclassified from AOCI into net income – effective portion	(119)	(123)
Cash flow hedges \| Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) recognized in OCI – effective portion	(478)	153
Gains/(Losses) reclassified from AOCI into net income – effective portion	(118)	(124)
Cash flow hedges \| Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) recognized in OCI – effective portion	0	1
Gains/(Losses) reclassified from AOCI into net income – effective portion	(1)	1
Net investment hedges \| Foreign currency debt
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) recognized in OCI – effective portion	(16)	2
Fair value hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) on derivative instruments	1,059	(274)
Gains/(Losses) related to hedged items	(1,059)	274
Fair value hedges \| Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) on derivative instruments	402	0
Gains/(Losses) related to hedged items	(402)	0
Fair value hedges \| Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) on derivative instruments	657	(274)
Gains/(Losses) related to hedged items	$ (657)	$ 274

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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-Publisher FASB
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- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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+ References

No definition available.

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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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- 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).

+ References

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