Collaborative Arrangements - Financial Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales	$ 15,962	$ 14,959	$ 45,485	$ 45,453
Collaborative Arrangement, Revenue Not from Contract with Customer, Statement of Income or Comprehensive Income [Extensible Enumeration]			Sales
Cost of sales	4,264	3,934	$ 12,214	13,530
Selling, general and administrative	2,519	2,520	7,700	7,355
Research and development	3,307	4,399	20,904	9,773
Payables included in Accrued and other liabilities	23,094		23,094		$ 24,239
Amortization			1,582	1,623
Alliance revenue - Lenvima
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Amortization	81		154
AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue from collaborative arrangement	325	294	958	868
AstraZeneca | Collaborative Arrangement | Alliance revenue - Lynparza
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue from collaborative arrangement	299	284	884	825
AstraZeneca | Collaborative Arrangement | Alliance revenue - Koselugo
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue from collaborative arrangement	26	10	74	43
Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue from collaborative arrangement	260	202	734	660
Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue from collaborative arrangement	92	88	259	258
Other current assets | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Receivables included in Other current assets	337		337		303
Other current assets | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Receivables included in Other current assets	260		260		214
Other current assets | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Receivables included in Other current assets	157		157		143
Accounts Payable and Accrued Liabilities | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payables included in Accrued and other liabilities	257		257		123
Accounts Payable and Accrued Liabilities | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payables included in Accrued and other liabilities	125		125		0
Accounts Payable and Accrued Liabilities | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payables included in Accrued and other liabilities	82		82		80
Accounts Payable and Accrued Liabilities | Ridgeback Biotherapeutics LP | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payables included in Accrued and other liabilities	242		242		348
Other Noncurrent Liabilities | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payables included in Other Noncurrent Liabilities	600		600		$ 600
Revenue | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales	165	151	472	454
Revenue | Bayer AG | Collaborative Arrangement | Adempas
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales	65	57	189	181
Revenue | Bayer AG | Collaborative Arrangement | Verquvo
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales	8	6	24	15
Revenue | Ridgeback Biotherapeutics LP | Collaborative Arrangement | Lagevrio
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales	640	436	1,236	4,859
Cost of sales | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cost of sales	82	64	230	425
Amortization of intangible assets				250
Cost of sales | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cost of sales	137	53	320	159
Cost of sales | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cost of sales	53	55	165	158
Cost of sales | Ridgeback Biotherapeutics LP | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cost of sales	348	244	762	2,586
Selling, general and administrative | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Selling, general and administrative	44	45	143	135
Selling, general and administrative | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Selling, general and administrative	46	42	145	115
Selling, general and administrative | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Selling, general and administrative	33	42	100	107
Selling, general and administrative | Ridgeback Biotherapeutics LP | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Selling, general and administrative	21	48	72	117
Research and development | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development	23	28	65	79
Research and development | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development	5	24	61	128
Research and development | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development	26	18	76	52
Research and development | Ridgeback Biotherapeutics LP | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development	$ 8	$ 18	$ 33	$ 74