ACQUISITIONS, DIVESTITURES, LICENSING AND OTHER ARRANGEMENTS - Licensing and Other Arrangements (Details) $ in Millions	12 Months Ended
	Dec. 31, 2025 USD ($) immunologyAsset	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contingent milestone income	$ (40)	$ (74)	$ (91)
Amortization of deferred income	(48)	(48)	(51)
Total	$ (1,093)	(736)	(1,488)
Number of immunology assets \| immunologyAsset	5
Keytruda Royalties
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty income, nonoperating	$ (588)	(546)	(1,186)
Royalty income, nonoperating	588	546	1,186
Tecentriq Royalties
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty income, nonoperating	(47)	(47)	(107)
Royalty income, nonoperating	47	47	107
Other royalties and licensing income
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty income, nonoperating	(370)	(21)	(53)
Royalty income, nonoperating	370	$ 21	$ 53
Other Royalties and Licensing Income, Out-License of Immunology Assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty income, nonoperating	(85)
Royalty income, nonoperating	85
Other Royalties and Licensing Income, Amendment Of Pre-Existing Out-Licensing Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty income, nonoperating	(170)
Royalty income, nonoperating	$ 170