REVENUES - Summary of Disaggregation of Revenues (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation of Revenue [Line Items]
Total revenues	$ 6,954	$ 6,599	$ 13,640	$ 12,951
U.S.
Disaggregation of Revenue [Line Items]
Total revenues	4,941	4,784	9,574	9,236
Europe
Disaggregation of Revenue [Line Items]
Total revenues	1,133	1,027	2,292	2,106
Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	879	789	1,774	1,610
Total product sales
Disaggregation of Revenue [Line Items]
Total revenues	6,912	6,564	13,559	12,870
Total product sales | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	4,916	4,777	9,525	9,211
Total product sales | Europe
Disaggregation of Revenue [Line Items]
Total revenues	1,118	999	2,262	2,052
Total product sales | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	878	788	1,772	1,607
Total HIV
Disaggregation of Revenue [Line Items]
Total revenues	4,745	4,626	9,088	8,816
Total HIV | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	3,821	3,778	7,226	7,142
Total HIV | Europe
Disaggregation of Revenue [Line Items]
Total revenues	571	521	1,167	1,049
Total HIV | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	353	326	695	624
Biktarvy
Disaggregation of Revenue [Line Items]
Total revenues	3,232	2,979	6,177	5,656
Biktarvy | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	2,585	2,439	4,900	4,600
Biktarvy | Europe
Disaggregation of Revenue [Line Items]
Total revenues	370	302	735	606
Biktarvy | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	277	237	542	449
Descovy
Disaggregation of Revenue [Line Items]
Total revenues	485	516	911	965
Descovy | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	434	460	805	855
Descovy | Europe
Disaggregation of Revenue [Line Items]
Total revenues	25	25	51	50
Descovy | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	26	31	55	60
Genvoya
Disaggregation of Revenue [Line Items]
Total revenues	440	540	843	1,041
Genvoya | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	372	455	704	872
Genvoya | Europe
Disaggregation of Revenue [Line Items]
Total revenues	45	56	95	111
Genvoya | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	23	29	44	58
Odefsey
Disaggregation of Revenue [Line Items]
Total revenues	315	351	626	668
Odefsey | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	233	267	457	497
Odefsey | Europe
Disaggregation of Revenue [Line Items]
Total revenues	72	74	148	149
Odefsey | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	10	11	21	22
Revenue share - Symtuza
Disaggregation of Revenue [Line Items]
Total revenues	168	120	309	259
Revenue share - Symtuza | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	131	84	236	182
Revenue share - Symtuza | Europe
Disaggregation of Revenue [Line Items]
Total revenues	34	33	67	70
Revenue share - Symtuza | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	3	3	6	7
Other HIV
Disaggregation of Revenue [Line Items]
Total revenues	105	120	222	228
Other HIV | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	65	74	125	136
Other HIV | Europe
Disaggregation of Revenue [Line Items]
Total revenues	25	31	70	63
Other HIV | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	15	15	27	28
Total Liver Disease
Disaggregation of Revenue [Line Items]
Total revenues	832	711	1,569	1,386
Total Liver Disease | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	431	356	816	674
Total Liver Disease | Europe
Disaggregation of Revenue [Line Items]
Total revenues	142	131	279	271
Total Liver Disease | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	259	225	474	441
Sofosbuvir/Velpatasvir
Disaggregation of Revenue [Line Items]
Total revenues	476	397	881	782
Sofosbuvir/Velpatasvir | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	267	223	515	427
Sofosbuvir/Velpatasvir | Europe
Disaggregation of Revenue [Line Items]
Total revenues	84	84	163	174
Sofosbuvir/Velpatasvir | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	126	90	203	181
Vemlidy
Disaggregation of Revenue [Line Items]
Total revenues	243	219	467	418
Vemlidy | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	117	96	212	183
Vemlidy | Europe
Disaggregation of Revenue [Line Items]
Total revenues	11	10	22	19
Vemlidy | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	115	113	233	216
Other Liver Disease
Disaggregation of Revenue [Line Items]
Total revenues	113	95	221	186
Other Liver Disease | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	47	37	89	64
Other Liver Disease | Europe
Disaggregation of Revenue [Line Items]
Total revenues	47	37	94	78
Other Liver Disease | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	19	21	38	44
Veklury
Disaggregation of Revenue [Line Items]
Total revenues	214	256	769	829
Veklury | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	76	97	391	349
Veklury | Europe
Disaggregation of Revenue [Line Items]
Total revenues	53	52	123	163
Veklury | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	85	107	255	317
Total Oncology
Disaggregation of Revenue [Line Items]
Total revenues	841	728	1,629	1,398
Total Oncology | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	474	462	904	893
Total Oncology | Europe
Disaggregation of Revenue [Line Items]
Total revenues	275	215	537	417
Total Oncology | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	92	51	188	88
Total Cell Therapy
Disaggregation of Revenue [Line Items]
Total revenues	521	469	1,001	916
Total Cell Therapy | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	250	272	475	542
Total Cell Therapy | Europe
Disaggregation of Revenue [Line Items]
Total revenues	206	162	400	310
Total Cell Therapy | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	66	34	126	65
Tecartus
Disaggregation of Revenue [Line Items]
Total revenues	107	88	207	177
Tecartus | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	63	56	118	114
Tecartus | Europe
Disaggregation of Revenue [Line Items]
Total revenues	37	29	73	56
Tecartus | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	7	4	16	6
Yescarta
Disaggregation of Revenue [Line Items]
Total revenues	414	380	794	739
Yescarta | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	186	217	357	427
Yescarta | Europe
Disaggregation of Revenue [Line Items]
Total revenues	169	133	327	254
Yescarta | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	58	30	110	58
Trodelvy
Disaggregation of Revenue [Line Items]
Total revenues	320	260	628	482
Trodelvy | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	224	189	429	351
Trodelvy | Europe
Disaggregation of Revenue [Line Items]
Total revenues	69	53	137	107
Trodelvy | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	26	17	62	23
Total Other
Disaggregation of Revenue [Line Items]
Total revenues	280	243	504	442
Total Other | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	115	85	188	153
Total Other | Europe
Disaggregation of Revenue [Line Items]
Total revenues	77	80	156	152
Total Other | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	88	78	160	137
AmBisome
Disaggregation of Revenue [Line Items]
Total revenues	151	151	294	267
AmBisome | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	17	20	31	27
AmBisome | Europe
Disaggregation of Revenue [Line Items]
Total revenues	69	69	139	129
AmBisome | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	65	61	124	111
Other
Disaggregation of Revenue [Line Items]
Total revenues	130	92	209	175
Other | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	98	64	156	127
Other | Europe
Disaggregation of Revenue [Line Items]
Total revenues	8	10	18	22
Other | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	24	17	36	26
Royalty, contract and other revenues
Disaggregation of Revenue [Line Items]
Total revenues	41	35	81	81
Royalty, contract and other revenues | U.S.
Disaggregation of Revenue [Line Items]
Total revenues	25	6	49	25
Royalty, contract and other revenues | Europe
Disaggregation of Revenue [Line Items]
Total revenues	15	28	30	54
Royalty, contract and other revenues | Rest of World
Disaggregation of Revenue [Line Items]
Total revenues	$ 1	$ 1	$ 2	$ 3