Stock Compensation Summary of restricted stock activity (Details) - Restricted Stock and Restricted Stock Units - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested, beginning of year - shares	1,708	1,673	1,166
Granted - shares	287	772	776
Vested - shares	(469)	(507)	(109)
Forfeited - shares	(340)	(230)	(160)
Non-vested, end of year - shares	1,186	1,708	1,673
Non-vested, beginning of year - weighted-average grant-date fair value	$ 65	$ 65	$ 63
Granted - weighted average grant-date fair value	55	63	65
Vested - weighted-average grant-date fair value	68	59	58
Forfeited - weighted-average grant-date fair value	62	64	65
Non-vested, end of year - weighted-average grant-date fair value	$ 61	$ 65	$ 65
Total fair value of restricted stock and restricted stock units vested during period	$ 27	$ 35	$ 5

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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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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