EARNINGS (LOSS) PER SHARE - Summary of the Calculation of Basic and Diluted (Loss) Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Earnings Per Share [Abstract]
Net (loss) income attributable to Gilead	$ (4,170)	$ 1,010
Shares used in basic (loss) earnings per share attributable to Gilead calculation (in shares)	1,247	1,248
Dilutive effect of stock options and equivalents (in shares)	0	13
Shares used in diluted (loss) earnings per share attributable to Gilead calculation (in shares)	1,247	1,261
Basic (loss) earnings per share attributable to Gilead (in dollars per share)	$ (3.34)	$ 0.81
Diluted earnings (loss) per share attributable to Gilead (in dollars per share)	$ (3.34)	$ 0.80