Other assets impairments, restructuring and other items - Schedule of Other Assets Impairments, Restructuring and Other Items (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Restructuring and Impairment Costs [Line Items]
Impairments of long-lived tangible assets	[1]	$ 26	$ 56	$ 106	$ 408
Contingent consideration		9	(179)	(7)	(96)
Restructuring		28	9	96	82
Other		(1)	15	32	10
Total		$ 62	$ (98)	$ 227	$ 404

[1] Including impairments related to exit and disposal activities.