Equity method investments - Unaudited financial information (Parenthetical) (Detail) - USD ($) $ in Billions	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019
The Kraft Heinz Company [Member]
Schedule of Equity Method Investments [Line Items]
Goodwill and identifiable intangible asset impairment charges	$ 3.2	$ 1.1

Total loss recognized during the period from the impairment of goodwill plus the loss recognized in the period resulting from the impairment of the carrying amount of intangible assets, other than goodwill.

No definition available.

Name:	us-gaap_GoodwillAndIntangibleAssetImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration