Financial Instruments - Pre-Tax Gains and Losses of Derivative and Non-Derivative Instruments Designated as Hedges (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 29, 2018	Sep. 30, 2017	Sep. 24, 2016
Cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) recognized in OCI - effective portion	$ 683	$ 1,804	$ 52
Gains/(Losses) reclassified from AOCI into net income - effective portion	(481)	1,956	874
Cash flow hedges \| Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) recognized in OCI - effective portion	682	1,797	109
Gains/(Losses) reclassified from AOCI into net income - effective portion	(482)	1,958	885
Cash flow hedges \| Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) recognized in OCI - effective portion	1	7	(57)
Gains/(Losses) reclassified from AOCI into net income - effective portion	1	(2)	(11)
Net investment hedges \| Foreign currency debt
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) recognized in OCI - effective portion	4	67	(258)
Fair value hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) on derivative instruments	(1,531)	(810)	341
Gains/(Losses) related to hedged items	1,530	810	(341)
Fair value hedges \| Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) on derivative instruments	(168)	0	0
Gains/(Losses) related to hedged items	167	0	0
Fair value hedges \| Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) on derivative instruments	(1,363)	(810)	341
Gains/(Losses) related to hedged items	$ 1,363	$ 810	$ (341)

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

+ References

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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.

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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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