Accounting Policies - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 26, 2020	Dec. 28, 2019
Accounting Policies [Abstract]
Obligations placed in accounts payable tracking system	$ 893	$ 812
Obligations sold by participating suppliers	651	$ 605
Sales | Trade Accounts Receivable
Prior Period Reclassification Adjustment	$ 14