Income Taxes, Uncertain Tax Positions (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 26, 2020	Sep. 28, 2019
Gross Unrecognized Tax Benefits [Roll Forward]
Beginning unrecognized tax benefits	$ 165	$ 74
Gross increases - tax positions in prior periods	13	2
Gross decreases - tax positions in prior periods	(12)	0
Gross increases - current period tax positions	0	6
Gross increases - from RPC acquisition	7	88
Settlements	(1)	(1)
Lapse of statue of limitations	(4)	(4)
Ending unrecognized tax benefits	168	$ 165
Unrecognized tax benefits that would affect effective tax rate if recognized	161
Interest and penalties accrued for uncertain tax positions	$ 40

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Amount of unrecognized tax benefits.

+ References

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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Amount of increase in unrecognized tax benefits resulting from acquisitions.

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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