Debt - Summary of Term Debt (Details) $ in Millions	6 Months Ended
Mar. 28, 2020 USD ($)	Mar. 28, 2020 EUR (€)	Sep. 28, 2019 USD ($)
Debt Instrument [Line Items]
Total term debt	$ 97,968		$ 101,679
Unamortized premium/(discount) and issuance costs, net	(220)		(224)
Hedge accounting fair value adjustments	1,730		612
Less: Current portion of term debt	(10,392)		(10,260)
Total non-current portion of term debt	89,086		91,807
2013 – 2019 debt issuances \| Floating-rate notes
Debt Instrument [Line Items]
Total term debt	$ 3,250		$ 4,250
Debt instrument, maturity year (calendar), start	2020
Debt instrument, maturity year (calendar), end	2022
2013 – 2019 debt issuances \| Floating-rate notes \| Minimum
Debt Instrument [Line Items]
Debt instrument, effective interest rate	1.80%	1.80%	2.25%
2013 – 2019 debt issuances \| Floating-rate notes \| Maximum
Debt Instrument [Line Items]
Debt instrument, effective interest rate	2.81%	2.81%	3.28%
2013 – 2019 debt issuances \| Fixed-rate notes
Debt Instrument [Line Items]
Total term debt	$ 92,554		$ 97,429
Debt instrument, maturity year (calendar), start	2020
Debt instrument, maturity year (calendar), end	2049
2013 – 2019 debt issuances \| Fixed-rate notes \| Minimum
Debt Instrument [Line Items]
Debt instrument, stated interest rate	0.35%	0.35%
Debt instrument, effective interest rate	0.28%	0.28%	0.28%
2013 – 2019 debt issuances \| Fixed-rate notes \| Maximum
Debt Instrument [Line Items]
Debt instrument, stated interest rate	4.65%	4.65%
Debt instrument, effective interest rate	4.78%	4.78%	4.78%
First quarter 2020 debt issuance
Debt Instrument [Line Items]
Debt instrument, face amount \| €		€ 2,000,000,000
First quarter 2020 debt issuance \| Fixed-rate notes
Debt Instrument [Line Items]
Total term debt	$ 2,164		$ 0
Debt instrument, maturity year (calendar), start	2025
Debt instrument, maturity year (calendar), end	2031
Debt instrument, effective interest rate			0.00%
First quarter 2020 debt issuance \| Fixed-rate notes \| Minimum
Debt Instrument [Line Items]
Debt instrument, stated interest rate	0.00%	0.00%
Debt instrument, effective interest rate	0.03%	0.03%
First quarter 2020 debt issuance \| Fixed-rate notes \| Maximum
Debt Instrument [Line Items]
Debt instrument, stated interest rate	0.50%	0.50%
Debt instrument, effective interest rate	0.56%	0.56%

Latest year the outstanding debt instruments are required to be repaid.

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Earliest year the outstanding debt instruments are required to be repaid.

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- Definition

Amount as of the balance sheet date of the adjustment to the carrying value of an interest bearing hedged item made under an interest rate fair value hedge.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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- Definition

Face (par) amount of debt instrument at time of issuance.

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- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Contractual interest rate for funds borrowed, under the debt agreement.

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- Definition

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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Amount of unamortized debt discount (premium) and debt issuance costs.

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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