Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Oct. 01, 2017	Sep. 25, 2016	Oct. 01, 2017	Sep. 25, 2016	Dec. 25, 2016	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Fiscal year duration			371 days		364 days
First quarter duration	98 days	91 days	280 days	273 days
Minimum
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Fiscal year duration			364 days
Maximum
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Fiscal year duration			371 days
Revenue | Expected adjustment | Accounting Standards Update 2014-09 | Retained Earnings
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cumulative effect of adopting ASU 2014-09						$ 3
Operating Income | Expected adjustment | Accounting Standards Update 2014-09 | Retained Earnings
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cumulative effect of adopting ASU 2014-09						$ 2