REVENUES - Summary of Disaggregation of Revenues (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Total revenues	$ 27,116	$ 27,281	$ 27,305
U.S.
Disaggregation of Revenue [Line Items]
Total revenues	19,438	18,884	19,267
Europe
Disaggregation of Revenue [Line Items]
Total revenues	4,310	4,469	4,874
Other International
Disaggregation of Revenue [Line Items]
Total revenues	3,368	3,928	3,164
Product sales
Disaggregation of Revenue [Line Items]
Total revenues	26,934	26,982	27,008
Product sales | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	19,377	18,716	19,176
Product sales | Europe
Disaggregation of Revenue [Line Items]
Total revenues	4,197	4,342	4,678
Product sales | Other International
Disaggregation of Revenue [Line Items]
Total revenues	3,361	3,924	3,154
Total HIV
Disaggregation of Revenue [Line Items]
Total revenues	18,175	17,194	16,315
Total HIV | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	14,848	13,820	12,828
Total HIV | Europe
Disaggregation of Revenue [Line Items]
Total revenues	2,102	2,219	2,366
Total HIV | Other International
Disaggregation of Revenue [Line Items]
Total revenues	1,226	1,155	1,121
Biktarvy
Disaggregation of Revenue [Line Items]
Total revenues	11,850	10,390	8,624
Biktarvy | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	9,692	8,510	7,049
Biktarvy | Europe
Disaggregation of Revenue [Line Items]
Total revenues	1,253	1,103	969
Biktarvy | Other International
Disaggregation of Revenue [Line Items]
Total revenues	905	777	606
Complera/Eviplera
Disaggregation of Revenue [Line Items]
Total revenues	129	200	258
Complera/Eviplera | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	47	74	102
Complera/Eviplera | Europe
Disaggregation of Revenue [Line Items]
Total revenues	70	113	142
Complera/Eviplera | Other International
Disaggregation of Revenue [Line Items]
Total revenues	12	13	14
Descovy
Disaggregation of Revenue [Line Items]
Total revenues	1,985	1,872	1,700
Descovy | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	1,771	1,631	1,397
Descovy | Europe
Disaggregation of Revenue [Line Items]
Total revenues	100	118	164
Descovy | Other International
Disaggregation of Revenue [Line Items]
Total revenues	114	123	139
Genvoya
Disaggregation of Revenue [Line Items]
Total revenues	2,060	2,404	2,879
Genvoya | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	1,752	1,983	2,267
Genvoya | Europe
Disaggregation of Revenue [Line Items]
Total revenues	205	284	391
Genvoya | Other International
Disaggregation of Revenue [Line Items]
Total revenues	103	136	221
Odefsey
Disaggregation of Revenue [Line Items]
Total revenues	1,350	1,469	1,568
Odefsey | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	1,012	1,058	1,076
Odefsey | Europe
Disaggregation of Revenue [Line Items]
Total revenues	294	364	440
Odefsey | Other International
Disaggregation of Revenue [Line Items]
Total revenues	44	47	52
Stribild
Disaggregation of Revenue [Line Items]
Total revenues	101	127	189
Stribild | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	72	88	132
Stribild | Europe
Disaggregation of Revenue [Line Items]
Total revenues	21	29	43
Stribild | Other International
Disaggregation of Revenue [Line Items]
Total revenues	8	10	14
Truvada
Disaggregation of Revenue [Line Items]
Total revenues	114	147	371
Truvada | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	82	113	314
Truvada | Europe
Disaggregation of Revenue [Line Items]
Total revenues	13	15	22
Truvada | Other International
Disaggregation of Revenue [Line Items]
Total revenues	19	18	35
Revenue share - Symtuza
Disaggregation of Revenue [Line Items]
Total revenues	529	530	531
Revenue share - Symtuza | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	382	348	355
Revenue share - Symtuza | Europe
Disaggregation of Revenue [Line Items]
Total revenues	133	168	165
Revenue share - Symtuza | Other International
Disaggregation of Revenue [Line Items]
Total revenues	13	14	11
Other HIV
Disaggregation of Revenue [Line Items]
Total revenues	56	57	195
Other HIV | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	37	15	136
Other HIV | Europe
Disaggregation of Revenue [Line Items]
Total revenues	12	24	30
Other HIV | Other International
Disaggregation of Revenue [Line Items]
Total revenues	7	17	29
Total Oncology
Disaggregation of Revenue [Line Items]
Total revenues	2,932	2,139	1,251
Total Oncology | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	1,833	1,494	912
Total Oncology | Europe
Disaggregation of Revenue [Line Items]
Total revenues	875	573	303
Total Oncology | Other International
Disaggregation of Revenue [Line Items]
Total revenues	224	73	36
Total Cell Therapy
Disaggregation of Revenue [Line Items]
Total revenues	1,869	1,459	871
Total Cell Therapy | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	1,055	968	542
Total Cell Therapy | Europe
Disaggregation of Revenue [Line Items]
Total revenues	658	430	293
Total Cell Therapy | Other International
Disaggregation of Revenue [Line Items]
Total revenues	156	60	36
Tecartus
Disaggregation of Revenue [Line Items]
Total revenues	370	299	176
Tecartus | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	245	221	136
Tecartus | Europe
Disaggregation of Revenue [Line Items]
Total revenues	110	75	40
Tecartus | Other International
Disaggregation of Revenue [Line Items]
Total revenues	15	3	0
Yescarta
Disaggregation of Revenue [Line Items]
Total revenues	1,498	1,160	695
Yescarta | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	811	747	406
Yescarta | Europe
Disaggregation of Revenue [Line Items]
Total revenues	547	355	253
Yescarta | Other International
Disaggregation of Revenue [Line Items]
Total revenues	140	57	36
Trodelvy
Disaggregation of Revenue [Line Items]
Total revenues	1,063	680	380
Trodelvy | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	777	525	370
Trodelvy | Europe
Disaggregation of Revenue [Line Items]
Total revenues	217	143	10
Trodelvy | Other International
Disaggregation of Revenue [Line Items]
Total revenues	68	12	0
Total Liver Disease
Disaggregation of Revenue [Line Items]
Total revenues	2,784	2,798	2,850
Total Liver Disease | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	1,421	1,440	1,415
Total Liver Disease | Europe
Disaggregation of Revenue [Line Items]
Total revenues	511	525	525
Total Liver Disease | Other International
Disaggregation of Revenue [Line Items]
Total revenues	852	833	910
Total HCV
Disaggregation of Revenue [Line Items]
Total revenues	1,767	1,810	1,881
Total HCV | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	1,002	1,005	1,018
Total HCV | Europe
Disaggregation of Revenue [Line Items]
Total revenues	378	413	421
Total HCV | Other International
Disaggregation of Revenue [Line Items]
Total revenues	386	392	442
Ledipasvir/Sofosbuvir
Disaggregation of Revenue [Line Items]
Total revenues	70	115	212
Ledipasvir/Sofosbuvir | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	39	46	84
Ledipasvir/Sofosbuvir | Europe
Disaggregation of Revenue [Line Items]
Total revenues	12	17	31
Ledipasvir/Sofosbuvir | Other International
Disaggregation of Revenue [Line Items]
Total revenues	19	51	97
Sofosbuvir/Velpatasvir
Disaggregation of Revenue [Line Items]
Total revenues	1,537	1,530	1,462
Sofosbuvir/Velpatasvir | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	859	844	815
Sofosbuvir/Velpatasvir | Europe
Disaggregation of Revenue [Line Items]
Total revenues	323	355	316
Sofosbuvir/Velpatasvir | Other International
Disaggregation of Revenue [Line Items]
Total revenues	355	331	331
Other HCV
Disaggregation of Revenue [Line Items]
Total revenues	160	166	207
Other HCV | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	104	115	119
Other HCV | Europe
Disaggregation of Revenue [Line Items]
Total revenues	43	40	74
Other HCV | Other International
Disaggregation of Revenue [Line Items]
Total revenues	12	10	14
Total HBV/HDV
Disaggregation of Revenue [Line Items]
Total revenues	1,017	988	969
Total HBV/HDV | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	418	435	397
Total HBV/HDV | Europe
Disaggregation of Revenue [Line Items]
Total revenues	133	112	104
Total HBV/HDV | Other International
Disaggregation of Revenue [Line Items]
Total revenues	466	441	468
Vemlidy
Disaggregation of Revenue [Line Items]
Total revenues	862	842	814
Vemlidy | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	410	429	384
Vemlidy | Europe
Disaggregation of Revenue [Line Items]
Total revenues	38	35	34
Vemlidy | Other International
Disaggregation of Revenue [Line Items]
Total revenues	414	379	396
Viread
Disaggregation of Revenue [Line Items]
Total revenues	83	91	111
Viread | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	8	6	11
Viread | Europe
Disaggregation of Revenue [Line Items]
Total revenues	22	23	28
Viread | Other International
Disaggregation of Revenue [Line Items]
Total revenues	52	62	72
Other HB/HDV
Disaggregation of Revenue [Line Items]
Total revenues	72	55	44
Other HB/HDV | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	0	0	2
Other HB/HDV | Europe
Disaggregation of Revenue [Line Items]
Total revenues	72	55	42
Other HB/HDV | Other International
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Veklury
Disaggregation of Revenue [Line Items]
Total revenues	2,184	3,905	5,565
Veklury | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	972	1,575	3,640
Veklury | Europe
Disaggregation of Revenue [Line Items]
Total revenues	408	702	1,095
Veklury | Other International
Disaggregation of Revenue [Line Items]
Total revenues	805	1,628	830
Total Other
Disaggregation of Revenue [Line Items]
Total revenues	859	946	1,027
Total Other | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	304	388	381
Total Other | Europe
Disaggregation of Revenue [Line Items]
Total revenues	301	323	389
Total Other | Other International
Disaggregation of Revenue [Line Items]
Total revenues	255	235	257
AmBisome
Disaggregation of Revenue [Line Items]
Total revenues	492	497	540
AmBisome | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	43	57	39
AmBisome | Europe
Disaggregation of Revenue [Line Items]
Total revenues	260	258	274
AmBisome | Other International
Disaggregation of Revenue [Line Items]
Total revenues	189	182	227
Letairis
Disaggregation of Revenue [Line Items]
Total revenues	142	196	206
Letairis | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	142	196	206
Letairis | Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Letairis | Other International
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Other
Disaggregation of Revenue [Line Items]
Total revenues	225	253	281
Other | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	118	135	136
Other | Europe
Disaggregation of Revenue [Line Items]
Total revenues	40	65	115
Other | Other International
Disaggregation of Revenue [Line Items]
Total revenues	66	53	30
Royalty, contract and other revenues
Disaggregation of Revenue [Line Items]
Total revenues	182	299	297
Royalty, contract and other revenues | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	62	168	91
Royalty, contract and other revenues | Europe
Disaggregation of Revenue [Line Items]
Total revenues	114	127	196
Royalty, contract and other revenues | Other International
Disaggregation of Revenue [Line Items]
Total revenues	$ 7	$ 4	$ 10