Shareholders' Equity - Earnings per share (Details) - shares shares in Thousands	3 Months Ended	12 Months Ended
Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 30, 2017	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Weighted-average shares outstanding for basic and diluted EPS
Basic weighted-average shares outstanding	240,248	246,136	253,904	260,497	263,295	264,624	267,114	270,489	250,196	266,380	270,774
Dilutive effect of stock options									3,041	2,370	1,591
Diluted weighted-average shares outstanding	242,569	249,378	257,177	263,672	263,295	266,989	269,299	272,830	253,237	268,750	272,365
Anti-dilutive effect of weighted average shares									1,300	1,600	2,000

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- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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- Definition

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

+ References

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-Publisher FASB
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- Definition

The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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