Segment Reporting - Sales of Company's Products (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Sales	$ 47,267	$ 48,047	$ 45,987
Other pharmaceutical [Member]
Segment Reporting Information [Line Items]
Sales	4,141	4,035	4,622
Total Pharmaceutical segment sales [Member]
Segment Reporting Information [Line Items]
Sales	40,601	41,289	39,267
Other segment [Member]
Segment Reporting Information [Line Items]
Sales	6,412	6,428	6,159
Total segment sales [Member]
Segment Reporting Information [Line Items]
Sales	47,013	47,717	45,426
Other [Member]
Segment Reporting Information [Line Items]
Sales	254	330	561
Zetia [Member] | Primary Care and Women's Health [Member]
Segment Reporting Information [Line Items]
Sales	2,567	2,428	2,297
Vytorin [Member] | Primary Care and Women's Health [Member]
Segment Reporting Information [Line Items]
Sales	1,747	1,882	2,014
Januvia [Member] | Primary Care and Women's Health [Member]
Segment Reporting Information [Line Items]
Sales	4,086	3,324	2,385
Janumet [Member] | Primary Care and Women's Health [Member]
Segment Reporting Information [Line Items]
Sales	1,659	1,363	954
Singulair [Member] | Primary Care and Women's Health [Member]
Segment Reporting Information [Line Items]
Sales	3,853	5,479	4,987
Nasonex [Member] | Primary Care and Women's Health [Member]
Segment Reporting Information [Line Items]
Sales	1,268	1,286	1,219
Clarinex [Member] | Primary Care and Women's Health [Member]
Segment Reporting Information [Line Items]
Sales	393	621	623
Dulera [Member] | Primary Care and Women's Health [Member]
Segment Reporting Information [Line Items]
Sales	207	96	8
Asmanex [Member] | Primary Care and Women's Health [Member]
Segment Reporting Information [Line Items]
Sales	185	206	208
Fosamax [Member] | Primary Care and Women's Health [Member]
Segment Reporting Information [Line Items]
Sales	676	855	926
NuvaRing [Member] | Primary Care and Women's Health [Member]
Segment Reporting Information [Line Items]
Sales	623	623	559
Follistim AQ [Member] | Primary Care and Women's Health [Member]
Segment Reporting Information [Line Items]
Sales	468	530	528
Implanon [Member] | Primary Care and Women's Health [Member]
Segment Reporting Information [Line Items]
Sales	348	294	236
Cerazette [Member] | Primary Care and Women's Health [Member]
Segment Reporting Information [Line Items]
Sales	271	268	209
Maxalt [Member] | Primary Care and Women's Health [Member]
Segment Reporting Information [Line Items]
Sales	638	639	550
Arcoxia [Member] | Primary Care and Women's Health [Member]
Segment Reporting Information [Line Items]
Sales	453	431	398
Avelox [Member] | Primary Care and Women's Health [Member]
Segment Reporting Information [Line Items]
Sales	201	322	316
Remicade [Member] | Hospital and Specialty [Member]
Segment Reporting Information [Line Items]
Sales	2,076	2,667	2,714
Simponi [Member] | Hospital and Specialty [Member]
Segment Reporting Information [Line Items]
Sales	331	264	97
Isentress [Member] | Hospital and Specialty [Member]
Segment Reporting Information [Line Items]
Sales	1,515	1,359	1,090
PegIntron [Member] | Hospital and Specialty [Member]
Segment Reporting Information [Line Items]
Sales	653	657	737
Cancidas [Member] | Hospital and Specialty [Member]
Segment Reporting Information [Line Items]
Sales	619	640	611
Victrelis [Member] | Hospital and Specialty [Member]
Segment Reporting Information [Line Items]
Sales	502	140
Invanz [Member] | Hospital and Specialty [Member]
Segment Reporting Information [Line Items]
Sales	445	406	362
Primaxin [Member] | Hospital and Specialty [Member]
Segment Reporting Information [Line Items]
Sales	384	515	610
Noxafil [Member] | Hospital and Specialty [Member]
Segment Reporting Information [Line Items]
Sales	258	230	198
Temodar [Member] | Hospital and Specialty [Member]
Segment Reporting Information [Line Items]
Sales	917	935	1,065
Emend [Member] | Hospital and Specialty [Member]
Segment Reporting Information [Line Items]
Sales	489	419	378
Cosopt/Trusopt [Member] | Hospital and Specialty [Member]
Segment Reporting Information [Line Items]
Sales	444	477	484
Bridion [Member] | Hospital and Specialty [Member]
Segment Reporting Information [Line Items]
Sales	261	201	103
Integrilin [Member] | Hospital and Specialty [Member]
Segment Reporting Information [Line Items]
Sales	211	230	266
Cozaar/Hyzaar [Member] | Diversified Brands [Member]
Segment Reporting Information [Line Items]
Sales	1,284	1,663	2,104
Propecia [Member] | Diversified Brands [Member]
Segment Reporting Information [Line Items]
Sales	424	447	447
Zocor [Member] | Diversified Brands [Member]
Segment Reporting Information [Line Items]
Sales	383	456	468
Claritin Rx [Member] | Diversified Brands [Member]
Segment Reporting Information [Line Items]
Sales	244	314	296
Remeron [Member] | Diversified Brands [Member]
Segment Reporting Information [Line Items]
Sales	232	241	223
Proscar [Member] | Diversified Brands [Member]
Segment Reporting Information [Line Items]
Sales	217	223	216
Vasotec/Vaseretic [Member] | Diversified Brands [Member]
Segment Reporting Information [Line Items]
Sales	192	231	255
Gardasil [Member] | Vaccines [Member]
Segment Reporting Information [Line Items]
Sales	1,631	1,209	988
ProQuad/M-M-R II/Varivax [Member] | Vaccines [Member]
Segment Reporting Information [Line Items]
Sales	1,273	1,202	1,378
Zostavax [Member] | Vaccines [Member]
Segment Reporting Information [Line Items]
Sales	651	332	243
RotaTeq [Member] | Vaccines [Member]
Segment Reporting Information [Line Items]
Sales	601	651	519
Pneumovax [Member] | Vaccines [Member]
Segment Reporting Information [Line Items]
Sales	$ 580	$ 498	$ 376