COLLABORATIONS AND OTHER ARRANGEMENTS (Details) € in Millions, shares in Millions, $ in Millions					1 Months Ended						3 Months Ended					12 Months Ended
	Dec. 21, 2021 USD ($)	Mar. 13, 2021 USD ($)	Jul. 13, 2020 USD ($)	May 27, 2020	Jan. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	May 31, 2023 USD ($)	Apr. 30, 2022 USD ($)	Aug. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($)	Dec. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2014	Jun. 30, 2023 shares	Jan. 30, 2023	Dec. 31, 2022 EUR (€)	Dec. 31, 2021 EUR (€)	Nov. 18, 2021 program	Dec. 15, 2020 USD ($)	Dec. 15, 2020 EUR (€)	Oct. 23, 2020 USD ($)	Jul. 17, 2020	Jun. 19, 2020	Dec. 31, 2019 shares
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Acquired in-process research and development expenses																$ 1,155	$ 944	$ 939
Research and development expenses																5,718	4,977	4,601
Other income (expense)																(198)	581	639
Write-off of finite-lived intangible asset																2,300	1,800	1,700
Cost of goods sold																6,498	5,657	6,601
Selling, general and administrative expenses																6,090	5,673	5,246
Abingworth
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum potential future milestone payments						$ 84					$ 84					84
Funding received																50
Abingworth | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Funding received						210
Arcus | Subsequent event
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Additional equity investment					$ 320
Option fee					$ 100
Abingworth
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone payment upon approval						84					84					84
Dragonfly Therapeutics Collaboration Agreement | Dragonfly Therapeutics, Inc.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payments to acquire in process research and development								$ 300
Additional payments to acquire in process research and development															$ 15
Merck Sharp & Dohme Corp
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percent of global and development and commercialization costs		60.00%
Revenues recognized																0	0	0
Option period to license certain inhibitors (in years)		5 years
Merck Sharp & Dohme Corp | Oral Formulation Product
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Net product sales threshold		$ 2,000
Percent of global product revenues		65.00%
Merck Sharp & Dohme Corp | Injectable Formulation Product
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Net product sales threshold		$ 3,500
Percent of global product revenues		65.00%
Merck Sharp & Dohme Corp | Merck
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percent of global and development and commercialization costs		40.00%
Arcus stock purchase agreement | Arcus
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Ownership percentage by noncontrolling owners																				19.90%
Janssen pharmaceuticals
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Purchase price of goods less specified amount, maximum percentage																			30.00%
Cost of goods sold																430	483	530
Period subject to termination (in years)																			10 years
Japan tobacco
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty expense																167	198	250
Cash paid										$ 559
Finite-lived intangible assets acquired										$ 550
Amortization useful life (in years)										9 years
Everest Medicines | Licensing Agreements
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Finite-lived intangible assets acquired														$ 50
Finite-lived intangible asset																											$ 175
Selling, general and administrative expenses																	406
Everest Medicines | Everest Medicines
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum potential future milestone payments														175			175
Upfront termination payments														280
Termination payments														84		196
Arcellx, Inc | Global Strategic Collaboration Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Acquired in-process research and development expenses																313
Payments to acquire shares																299
Percentage of profits earned																					50.00%
Maximum potential future milestone payments						1,500					1,500					1,500
Arcellx, Inc | Global Strategic Collaboration Agreement | Arcellx, Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of profits earned																					50.00%
Arcus | Subsequent event
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Ownership percentage					33.00%
Arcus | Arcus collaboration agreement and stock purchase agreements
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Acquired in-process research and development expenses																		625
Opt-in term (in years)				10 years
Number of clinical stage programs with exercise options | program																								3
Collaboration opt-in payments	$ 725
Arcus | Arcus collaboration agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum potential future milestone payments							$ 420
Option continuation payment waived			$ 100
Additional option fee on fourth, sixth, and eighth anniversaries			$ 100
Collaboration agreement, up-front fee paid							$ 35
Research and development expenses																189	187
Arcus | Arcus stock purchase agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum percentage of outstanding stock allowed to be purchased			35.00%
Purchase period (in years)			5 years
Restriction period (in years)			3 years
Number of shares (in shares) | shares																				14.8
Pionyr
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Ownership percentage																													49.90%
Other income (expense)													$ 70
Pionyr | Pionyr merger and option agreements
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Equity investments balance														0			0
Tizona
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Ownership percentage																												49.90%
Other income (expense)												$ 41
Tizona | Tizona merger and option agreements
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Equity investments balance						$ 0					0			0		$ 0	0
Galapagos | Fair Value, Nonrecurring
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Write-off of finite-lived intangible asset											$ 51
Galapagos | Amended 2019 agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential payment for adjustments of budgeted development costs																									$ 190	€ 160
Payment for adjustments of budgeted development costs in 2022														$ 60			$ 60	$ 130				€ 50	€ 110
Galapagos | Galapagos subscription agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Ownership percentage									25.80%
Shares of common stock acquired (in shares) | shares									6.8																					16.7
Maximum ownership percentage									29.90%
Standstill restricting term (in years)									10 years
Minimum ownership percentage									20.10%
Potential option exercise fee									$ 150
Payment of tiered royalties, low-end percentage									20.00%
Payment of tiered royalties, high-end percentage									24.00%