GOODWILL AND INTANGIBLE ASSETS - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended					12 Months Ended
	Dec. 31, 2025	Jun. 30, 2025	Sep. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Business Combination [Line Items]
Accumulated goodwill impairment losses	$ 0					$ 0
Aggregate amortization expense related to finite-lived intangible assets						2,400	$ 2,400	$ 2,300
Discount rate of acquired IPR&D					7.50%		7.25%	7.50%
In-process research and development impairments						590	$ 4,180	$ 50
Galapagos \| Fair Value, Nonrecurring
Business Combination [Line Items]
Aggregate amortization expense related to finite-lived intangible assets								$ 51
In Process Research And Development Bulevirtide
Business Combination [Line Items]
In-process research and development impairments	$ 400	$ 190				$ 590
In Process Research And Development Bulevirtide \| Fair Value, Nonrecurring
Business Combination [Line Items]
In-process research and development impairments					$ 50
In Process Research And Development Bulevirtide \| Measurement Input, Discount Rate
Business Combination [Line Items]
Discount rate, measurement input	7.75%	8.25%				7.75%
In Process Research And Development NSCLC
Business Combination [Line Items]
In-process research and development impairments			$ 1,800	$ 2,400
In Process Research And Development NSCLC \| Immunomedics, Inc. \| Measurement Input, Discount Rate
Business Combination [Line Items]
Discount rate, measurement input			7.00%	7.00%