ACQUISITIONS, DIVESTITURES, LICENSING AND OTHER ARRANGEMENTS - Licensing and Other Arrangements (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025 USD ($) immunologyAsset	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($) immunologyAsset	Sep. 30, 2024 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Contingent milestone income	$ 0	$ (13)	$ (40)	$ (38)
Amortization of deferred income	(12)	(12)	(36)	(36)
Royalty and licensing income	$ (276)	(180)	$ (697)	(532)
Number of immunology assets | immunologyAsset	5		5
Keytruda royalties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Royalty income, nonoperating	$ (150)	(137)	$ (434)	(407)
Tecentriq royalties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Royalty income, nonoperating	(12)	(12)	(34)	(35)
Other royalties and licensing income
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Royalty income, nonoperating	(102)	$ (6)	(152)	$ (16)
Other royalties and licensing income, out-license of immunology assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Royalty income, nonoperating	$ (85)		$ (85)