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Segment Reporting - Sales of Company's Products (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Sales	$ 60,115	$ 59,283	$ 48,704
Increase (decrease) in revenue hedging activities	244	810	(203)
Revenue related to the sale of the marketing rights	118	165	218
Operating Segments
Segment Reporting Information [Line Items]
Sales	59,208	57,555	48,322
Operating Segments | Pharmaceutical segment
Segment Reporting Information [Line Items]
Sales	53,583	52,005	42,754
Operating Segments | Pharmaceutical segment | Keytruda
Segment Reporting Information [Line Items]
Sales	25,011	20,937	17,186
Operating Segments | Pharmaceutical segment | Alliance revenue - Lynparza
Segment Reporting Information [Line Items]
Sales	1,199	1,116	989
Operating Segments | Pharmaceutical segment | Alliance revenue - Lenvima
Segment Reporting Information [Line Items]
Sales	960	876	704
Operating Segments | Pharmaceutical segment | Welireg
Segment Reporting Information [Line Items]
Sales	218	123	13
Operating Segments | Pharmaceutical segment | Gardasil/Gardasil 9
Segment Reporting Information [Line Items]
Sales	8,886	6,897	5,673
Operating Segments | Pharmaceutical segment | ProQuad/M-M-R II/Varivax
Segment Reporting Information [Line Items]
Sales	2,368	2,241	2,135
Operating Segments | Pharmaceutical segment | RotaTeq
Segment Reporting Information [Line Items]
Sales	769	783	807
Operating Segments | Pharmaceutical segment | Vaxneuvance
Segment Reporting Information [Line Items]
Sales	665	170	3
Operating Segments | Pharmaceutical segment | Pneumovax 23
Segment Reporting Information [Line Items]
Sales	412	602	893
Operating Segments | Pharmaceutical segment | Vaqta
Segment Reporting Information [Line Items]
Sales	180	173	179
Operating Segments | Pharmaceutical segment | Bridion
Segment Reporting Information [Line Items]
Sales	1,842	1,685	1,532
Operating Segments | Pharmaceutical segment | Prevymis
Segment Reporting Information [Line Items]
Sales	605	428	370
Operating Segments | Pharmaceutical segment | Dificid
Segment Reporting Information [Line Items]
Sales	302	263	175
Operating Segments | Pharmaceutical segment | Zerbaxa
Segment Reporting Information [Line Items]
Sales	218	169	(1)
Operating Segments | Pharmaceutical segment | Noxafil
Segment Reporting Information [Line Items]
Sales	213	238	259
Operating Segments | Pharmaceutical segment | Primaxin
Segment Reporting Information [Line Items]
Sales	213	239	259
Operating Segments | Pharmaceutical segment | Alliance revenue - Adempas/Verquvo
Segment Reporting Information [Line Items]
Sales	367	341	342
Operating Segments | Pharmaceutical segment | Adempas
Segment Reporting Information [Line Items]
Sales	255	238	252
Operating Segments | Pharmaceutical segment | Lagevrio
Segment Reporting Information [Line Items]
Sales	1,428	5,684	952
Operating Segments | Pharmaceutical segment | Isentress/Isentress HD
Segment Reporting Information [Line Items]
Sales	483	633	769
Operating Segments | Pharmaceutical segment | Belsomra
Segment Reporting Information [Line Items]
Sales	231	258	318
Operating Segments | Pharmaceutical segment | Simponi
Segment Reporting Information [Line Items]
Sales	710	706	825
Operating Segments | Pharmaceutical segment | Remicade
Segment Reporting Information [Line Items]
Sales	187	207	299
Operating Segments | Pharmaceutical segment | Januvia
Segment Reporting Information [Line Items]
Sales	2,189	2,813	3,324
Operating Segments | Pharmaceutical segment | Janumet
Segment Reporting Information [Line Items]
Sales	1,177	1,700	1,964
Operating Segments | Pharmaceutical segment | Other pharmaceutical
Segment Reporting Information [Line Items]
Sales	2,283	2,319	2,516
Operating Segments | Animal Health
Segment Reporting Information [Line Items]
Sales	5,625	5,550	5,568
Operating Segments | Animal Health | Livestock
Segment Reporting Information [Line Items]
Sales	3,337	3,300	3,295
Operating Segments | Animal Health | Companion Animal
Segment Reporting Information [Line Items]
Sales	2,288	2,250	2,273
Other
Segment Reporting Information [Line Items]
Sales	907	1,728	382
United States
Segment Reporting Information [Line Items]
Sales	28,480	27,206	22,425
United States | Operating Segments
Segment Reporting Information [Line Items]
Sales	28,343	26,811	22,159
United States | Operating Segments | Pharmaceutical segment
Segment Reporting Information [Line Items]
Sales	26,539	24,989	20,401
United States | Operating Segments | Pharmaceutical segment | Keytruda
Segment Reporting Information [Line Items]
Sales	15,114	12,686	9,765
United States | Operating Segments | Pharmaceutical segment | Alliance revenue - Lynparza
Segment Reporting Information [Line Items]
Sales	607	584	515
United States | Operating Segments | Pharmaceutical segment | Alliance revenue - Lenvima
Segment Reporting Information [Line Items]
Sales	657	579	417
United States | Operating Segments | Pharmaceutical segment | Welireg
Segment Reporting Information [Line Items]
Sales	209	123	13
United States | Operating Segments | Pharmaceutical segment | Alliance revenue - Reblozyl
Segment Reporting Information [Line Items]
Sales	168	123	0
United States | Operating Segments | Pharmaceutical segment | Gardasil/Gardasil 9
Segment Reporting Information [Line Items]
Sales	2,083	2,065	1,881
United States | Operating Segments | Pharmaceutical segment | ProQuad/M-M-R II/Varivax
Segment Reporting Information [Line Items]
Sales	1,837	1,724	1,629
United States | Operating Segments | Pharmaceutical segment | RotaTeq
Segment Reporting Information [Line Items]
Sales	493	508	473
United States | Operating Segments | Pharmaceutical segment | Vaxneuvance
Segment Reporting Information [Line Items]
Sales	561	163	3
United States | Operating Segments | Pharmaceutical segment | Pneumovax 23
Segment Reporting Information [Line Items]
Sales	127	346	547
United States | Operating Segments | Pharmaceutical segment | Vaqta
Segment Reporting Information [Line Items]
Sales	119	95	100
United States | Operating Segments | Pharmaceutical segment | Bridion
Segment Reporting Information [Line Items]
Sales	1,156	922	762
United States | Operating Segments | Pharmaceutical segment | Prevymis
Segment Reporting Information [Line Items]
Sales	264	188	153
United States | Operating Segments | Pharmaceutical segment | Dificid
Segment Reporting Information [Line Items]
Sales	274	241	166
United States | Operating Segments | Pharmaceutical segment | Zerbaxa
Segment Reporting Information [Line Items]
Sales	119	89	4
United States | Operating Segments | Pharmaceutical segment | Noxafil
Segment Reporting Information [Line Items]
Sales	32	51	60
United States | Operating Segments | Pharmaceutical segment | Primaxin
Segment Reporting Information [Line Items]
Sales	1	1	2
United States | Operating Segments | Pharmaceutical segment | Alliance revenue - Adempas/Verquvo
Segment Reporting Information [Line Items]
Sales	350	329	312
United States | Operating Segments | Pharmaceutical segment | Adempas
Segment Reporting Information [Line Items]
Sales	0	0	0
United States | Operating Segments | Pharmaceutical segment | Lagevrio
Segment Reporting Information [Line Items]
Sales	10	1,523	632
United States | Operating Segments | Pharmaceutical segment | Isentress/Isentress HD
Segment Reporting Information [Line Items]
Sales	215	274	294
United States | Operating Segments | Pharmaceutical segment | Belsomra
Segment Reporting Information [Line Items]
Sales	81	79	78
United States | Operating Segments | Pharmaceutical segment | Simponi
Segment Reporting Information [Line Items]
Sales	0	0	0
United States | Operating Segments | Pharmaceutical segment | Remicade
Segment Reporting Information [Line Items]
Sales	0	0	0
United States | Operating Segments | Pharmaceutical segment | Januvia
Segment Reporting Information [Line Items]
Sales	1,151	1,248	1,404
United States | Operating Segments | Pharmaceutical segment | Janumet
Segment Reporting Information [Line Items]
Sales	223	355	367
United States | Operating Segments | Pharmaceutical segment | Other pharmaceutical
Segment Reporting Information [Line Items]
Sales	688	693	824
United States | Operating Segments | Animal Health
Segment Reporting Information [Line Items]
Sales	1,804	1,822	1,758
United States | Operating Segments | Animal Health | Livestock
Segment Reporting Information [Line Items]
Sales	700	710	667
United States | Operating Segments | Animal Health | Companion Animal
Segment Reporting Information [Line Items]
Sales	1,104	1,112	1,091
United States | Other
Segment Reporting Information [Line Items]
Sales	137	395	266
Int’l
Segment Reporting Information [Line Items]
Sales	31,635	32,077	26,279
Int’l | Operating Segments
Segment Reporting Information [Line Items]
Sales	30,865	30,744	26,163
Int’l | Operating Segments | Pharmaceutical segment
Segment Reporting Information [Line Items]
Sales	27,044	27,016	22,353
Int’l | Operating Segments | Pharmaceutical segment | Keytruda
Segment Reporting Information [Line Items]
Sales	9,897	8,251	7,421
Int’l | Operating Segments | Pharmaceutical segment | Alliance revenue - Lynparza
Segment Reporting Information [Line Items]
Sales	592	532	473
Int’l | Operating Segments | Pharmaceutical segment | Alliance revenue - Lenvima
Segment Reporting Information [Line Items]
Sales	303	297	287
Int’l | Operating Segments | Pharmaceutical segment | Welireg
Segment Reporting Information [Line Items]
Sales	10	0	0
Int’l | Operating Segments | Pharmaceutical segment | Alliance revenue - Reblozyl
Segment Reporting Information [Line Items]
Sales	43	43	17
Int’l | Operating Segments | Pharmaceutical segment | Gardasil/Gardasil 9
Segment Reporting Information [Line Items]
Sales	6,803	4,832	3,792
Int’l | Operating Segments | Pharmaceutical segment | ProQuad/M-M-R II/Varivax
Segment Reporting Information [Line Items]
Sales	531	518	506
Int’l | Operating Segments | Pharmaceutical segment | RotaTeq
Segment Reporting Information [Line Items]
Sales	276	275	334
Int’l | Operating Segments | Pharmaceutical segment | Vaxneuvance
Segment Reporting Information [Line Items]
Sales	103	7	0
Int’l | Operating Segments | Pharmaceutical segment | Pneumovax 23
Segment Reporting Information [Line Items]
Sales	285	256	346
Int’l | Operating Segments | Pharmaceutical segment | Vaqta
Segment Reporting Information [Line Items]
Sales	61	78	79
Int’l | Operating Segments | Pharmaceutical segment | Bridion
Segment Reporting Information [Line Items]
Sales	686	762	770
Int’l | Operating Segments | Pharmaceutical segment | Prevymis
Segment Reporting Information [Line Items]
Sales	341	240	218
Int’l | Operating Segments | Pharmaceutical segment | Dificid
Segment Reporting Information [Line Items]
Sales	28	22	10
Int’l | Operating Segments | Pharmaceutical segment | Zerbaxa
Segment Reporting Information [Line Items]
Sales	100	79	(5)
Int’l | Operating Segments | Pharmaceutical segment | Noxafil
Segment Reporting Information [Line Items]
Sales	181	187	199
Int’l | Operating Segments | Pharmaceutical segment | Primaxin
Segment Reporting Information [Line Items]
Sales	211	238	258
Int’l | Operating Segments | Pharmaceutical segment | Alliance revenue - Adempas/Verquvo
Segment Reporting Information [Line Items]
Sales	16	12	30
Int’l | Operating Segments | Pharmaceutical segment | Adempas
Segment Reporting Information [Line Items]
Sales	255	238	252
Int’l | Operating Segments | Pharmaceutical segment | Lagevrio
Segment Reporting Information [Line Items]
Sales	1,418	4,161	320
Int’l | Operating Segments | Pharmaceutical segment | Isentress/Isentress HD
Segment Reporting Information [Line Items]
Sales	268	359	474
Int’l | Operating Segments | Pharmaceutical segment | Belsomra
Segment Reporting Information [Line Items]
Sales	150	179	241
Int’l | Operating Segments | Pharmaceutical segment | Simponi
Segment Reporting Information [Line Items]
Sales	710	706	825
Int’l | Operating Segments | Pharmaceutical segment | Remicade
Segment Reporting Information [Line Items]
Sales	187	207	299
Int’l | Operating Segments | Pharmaceutical segment | Januvia
Segment Reporting Information [Line Items]
Sales	1,039	1,565	1,920
Int’l | Operating Segments | Pharmaceutical segment | Janumet
Segment Reporting Information [Line Items]
Sales	954	1,344	1,597
Int’l | Operating Segments | Pharmaceutical segment | Other pharmaceutical
Segment Reporting Information [Line Items]
Sales	1,596	1,628	1,690
Int’l | Operating Segments | Animal Health
Segment Reporting Information [Line Items]
Sales	3,821	3,728	3,810
Int’l | Operating Segments | Animal Health | Livestock
Segment Reporting Information [Line Items]
Sales	2,637	2,590	2,628
Int’l | Operating Segments | Animal Health | Companion Animal
Segment Reporting Information [Line Items]
Sales	1,184	1,138	1,182
Int’l | Other
Segment Reporting Information [Line Items]
Sales	$ 770	$ 1,333	$ 116

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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