Cash, Cash Equivalents, Restricted Cash and Borrowings Interest Expense, net (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Dec. 29, 2018	Dec. 30, 2017	Sep. 29, 2018	Sep. 30, 2017	Oct. 01, 2016
Interest expense	$ (163)	$ (146)	$ (682)	$ (507)	$ (354)
Interest and investment income	75	17
Interest expense, net	(63)	(129)
Net periodic pension and postretirement benefit costs other than service costs	25	0
Interest expense, net	$ (63)	$ (129)	$ (574)	$ (385)	$ (260)

Amount of the cost of borrowed funds accounted for as interest expense.

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The net amount of operating interest income (expense).

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The net amount of nonoperating interest income (expense).

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Amount after accretion (amortization) of discount (premium), and investment expense, of interest income and dividend income on nonoperating securities.

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Amount of expense (reversal of expense) for net periodic benefit cost components, excluding service cost component, of defined benefit plan. Amount includes, but is not limited to, interest cost, expected (return) loss on plan asset, amortization of prior service cost (credit), amortization of (gain) loss, amortization of transition (asset) obligation, settlement (gain) loss, curtailment (gain) loss and certain termination benefits.

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