Divestitures and held for sale - Assets and liabilities held for sale table (Details) - USD ($) $ in Millions	Jun. 29, 2019	Dec. 29, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total current assets	$ 112	$ 0
Total noncurrent assets	1,188	0
Total Current liabilities	1	$ 0
North America | Cookies, fruit and fruit snacks businesses
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Inventory and other assets	112
Total current assets	112
Property and equipment	227
Goodwill and intangibles assets	956
Operating lease right-of-use assets	5
Total noncurrent assets	1,188
Total assets	1,300
Current operating lease liabilities	1
Total Current liabilities	1
Operating lease liabilities	4
Total liabilities	$ 5