EARNINGS PER SHARE - Schedule of the Calculation of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Earnings Per Share [Abstract]
Net income attributable to Gilead	$ 1,010	$ 19
Shares used in basic earnings per share attributable to Gilead calculation	1,248	1,255
Dilutive effect of stock options and equivalents	13	6
Shares used in diluted earnings per share attributable to Gilead calculation	1,261	1,262
Basic earnings per share attributable to Gilead (in dollars per share)	$ 0.81	$ 0.02
Diluted earnings per share attributable to Gilead (in dollars per share)	$ 0.80	$ 0.02