Contract Asset and Liabilities (Details) - USD ($) $ in Millions			3 Months Ended	9 Months Ended
Sep. 28, 2018	Dec. 30, 2017	Sep. 28, 2018	Sep. 28, 2018
Schedule Of Contract Assets And Liabilities [Line Items]
Contract assets - current	$ 813	$ 903	$ 813	$ 813
Contract assets - non-current	11	13	11	11
Contract liabilities - current	362	293	362	362
Contract liabilities - non-current	12	17	12	12
Contract assets part of receivable	506	234
Contract liability revenue recognized			37	164
Amortization of transition and project cots			43	83
Receivables, net
Schedule Of Contract Assets And Liabilities [Line Items]
Contract assets - current	711	844	711	711
Inventory, prepaid expenses and other current assets
Schedule Of Contract Assets And Liabilities [Line Items]
Contract assets - current	$ 102	$ 59	$ 102	$ 102

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