Collaborative Arrangements - Financial Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales	$ 15,035	$ 14,593	$ 29,522	$ 30,494
Cost of sales	4,024	4,216	7,951	9,596
Selling, general and administrative	2,702	2,512	5,182	4,834
Research and development	13,321	2,798	17,597	5,374
Payables included in Accrued and other liabilities	23,394		23,394		$ 24,239
Amortization			1,020	1,163
Alliance revenue - Lenvima
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Amortization			72
Other current assets | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Receivables included in Other current assets	332		332		303
Other current assets | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Receivables included in Other current assets	242		242		214
Other current assets | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Receivables included in Other current assets	144		144		143
Other current assets | Ridgeback Biotherapeutics LP | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Receivables included in Other current assets	51		51		0
Accounts Payable and Accrued Liabilities | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payables included in Accrued and other liabilities	260		260		123
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	30		30		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 | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Alliance revenue - profit sharing	335	299	633	574
Revenue | AstraZeneca | Collaborative Arrangement | Alliance revenue - Lynparza
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Alliance revenue - profit sharing	310	275	585	541
Revenue | AstraZeneca | Collaborative Arrangement | Alliance revenue - Koselugo
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Alliance revenue - profit sharing	25	24	48	33
Revenue | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Alliance revenue - profit sharing	242	231	474	459
Revenue | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Alliance revenue - profit sharing	68	98	167	170
Sales	142	167	308	303
Revenue | Bayer AG | Collaborative Arrangement | Adempas
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Net sales by Merck	65	63	125	124
Revenue | Bayer AG | Collaborative Arrangement | Verquvo
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Net sales by Merck	9	6	16	9
Revenue | Ridgeback Biotherapeutics LP | Collaborative Arrangement | Lagevrio
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales	203	1,177	595	4,424
Cost of sales | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cost of sales	78	62	148	361
Amortization of intangible assets				250
Cost of sales | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cost of sales	57	53	183	106
Cost of sales | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cost of sales	56	54	113	103
Cost of sales | Ridgeback Biotherapeutics LP | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cost of sales	193	615	414	2,341
Selling, general and administrative | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Selling, general and administrative	51	46	98	90
Selling, general and administrative | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Selling, general and administrative	48	42	99	73
Selling, general and administrative | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Selling, general and administrative	34	42	67	65
Selling, general and administrative | Ridgeback Biotherapeutics LP | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Selling, general and administrative	24	34	51	69
Research and development | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development	22	25	43	51
Research and development | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development	17	47	56	104
Research and development | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development	25	17	50	34
Research and development | Ridgeback Biotherapeutics LP | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development	$ 10	$ 30	$ 26	$ 56