Acquisitions and divestitures - Narrative (Details) - USD ($) $ in Millions			3 Months Ended		9 Months Ended
	Jun. 28, 2022	Apr. 16, 2021	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Business Acquisition [Line Items]
Adjustments to goodwill resulting from acquisitions and divestitures, net					$ 6
Goodwill			$ 14,845		14,845		$ 14,890
Payments to acquire business					0	$ 1,639
Acquired in-process research and development			0	$ 0	0	1,505
Loss on divestiture					565	$ 0
Gensenta Ilac Sanayi vs Ticaret
Business Acquisition [Line Items]
Proceeds from divestiture of business	$ 135
Including discontinued operation, assets	$ 76
Held-for-sale assets			94		94
Held-for-sale liabilities			18		18
Gensenta Ilac Sanayi vs Ticaret | Other Operating Income (Expense)
Business Acquisition [Line Items]
Loss on divestiture					565
Teneobio
Business Acquisition [Line Items]
Adjustments to goodwill resulting from acquisitions and divestitures, net					22
Cash purchase price					993
Maximum additional consideration due contingent on certain milestones			1,600		1,600
Contingent consideration					299
Acquired in-process research and development			991		991
Deferred tax liability			244		244
Goodwill			273		273
Teneobio | R & D Technology rights
Business Acquisition [Line Items]
Value of intangible assets acquired					$ 115
Weighted average period of amortization					10 years
Teneobio | Licensing rights
Business Acquisition [Line Items]
Value of intangible assets acquired					$ 41
Teneobio | In-process research and development | AMG 340
Business Acquisition [Line Items]
Acquired in-process research and development			$ 784		$ 784
Five Prime Therapeutics, Inc.
Business Acquisition [Line Items]
Payments to acquire business		$ 1,600
Acquired in-process research and development		1,500
Deferred tax asset		177
Other liabilities		$ 47