Leases - Balance sheet and other information (Details) - USD ($) $ in Millions	Mar. 30, 2019	Dec. 29, 2018
Operating leases:
Other assets	$ 301
Other assets	us-gaap:OtherAssets
Other current liabilities	$ 54
Other current liabilities	us-gaap:OtherLiabilitiesCurrent
Other liabilities	$ 250
Other liabilities	us-gaap:OtherLiabilities
Finance leases:
Property, plant and equipment, less accumulated amortization of $50 million	$ 117
Property, plant and equipment, less accumulated amortization of $50 million	us-gaap:PropertyPlantAndEquipmentNet
Accumulated amortization	$ 4,256	$ 4,203
Short-term and current portion of long-term debt	$ 7
Short-term and current portion of long-term debt	us-gaap:DebtCurrent
Long-term debt	$ 78
Long-term debt	us-gaap:LongTermDebtAndCapitalLeaseObligations
Weighted-average remaining lease term (in years)
Finance leases	14 years 2 months 12 days
Operating leases	10 years 4 months 24 days
Weighted-average discount rate
Finance leases	2.72%
Operating leases	4.47%
Finance leased assets
Finance leases:
Accumulated amortization	$ 50