Accounting Policies - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Mar. 30, 2019	Sep. 28, 2019	Dec. 30, 2018	Dec. 29, 2018
Impact of new accounting standards
Reclassification of tax effects relating to U.S. tax reform		$ 0
Operating lease right-of-use assets		464	$ 453	$ 0
Operating lease liabilities		471	$ 461
Obligations placed in accounts payable tracking system		809		893
Obligations sold by participating suppliers		572		$ 701
AOCI
Impact of new accounting standards
Reclassification of tax effects relating to U.S. tax reform	$ (22)
Retained earnings
Impact of new accounting standards
Reclassification of tax effects relating to U.S. tax reform	$ 22	$ 22