Acquisitions and divestitures - Narrative: Acquisition of ChemoCentryx Inc (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
	Oct. 20, 2022	Mar. 31, 2023	Dec. 31, 2022
Business Acquisition [Line Items]
Goodwill		$ 15,531	$ 15,529
ChemoCentryx, Inc.
Business Acquisition [Line Items]
Business acquisition, share price (in dollars per share)	$ 52.00
Business asset acquisition, consideration transferred	$ 3,900
Goodwill increase (decrease)		(4)
Cash payment	3,700
Business acquisition, cash consideration paid to equity holders for pre-acquisition services	$ 181
Finite-lived intangible assets – developed-product-technology rights		3,499
Inventories		$ 41
Business combination, turnover period of inventory acquired		13 months
Deferred tax liability		$ 516
Goodwill		663
ChemoCentryx, Inc. | Developed Technology Rights
Business Acquisition [Line Items]
Finite-lived intangible assets – developed-product-technology rights		$ 3,500
Weighted average period of amortization		11 years