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FAIR VALUE MEASUREMENTS - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
In-process research and development impairment	$ 0		$ 0	$ 2,700	$ 0
Fair Value, Nonrecurring \| In Process Research And Development Trodelvy For HR+/HER2-
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
In-process research and development impairment		$ 2,700		2,700
Market value \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term and long-term debt	21,200			21,200		$ 28,600
Market value \| Level 3 \| Immunomedics \| Fair Value, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Future royalties	1,100			1,100		1,300
Carrying value \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term and long-term debt, carrying values	24,100			24,100		25,600
Carrying value \| Level 3 \| Immunomedics \| Fair Value, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Future royalties	$ 1,100			$ 1,100		$ 1,100