Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 6,201	$ 89	$ 5,364
Other comprehensive income (loss):
Net foreign currency translation gain (loss), net of tax	(38)	(2)	6
Available-for-sale debt securities:
Net unrealized gain (loss), net of tax	(6)	43	54
Reclassifications to net income, net of tax	0	(42)	(1)
Net change	(6)	1	53
Cash flow hedges:
Net unrealized gain (loss), net of tax	129	(103)	72
Reclassifications to net income, net of tax	58	(41)	(126)
Net change	187	(144)	(54)
Other comprehensive income (loss)	143	(145)	5
Comprehensive income (loss)	6,344	(56)	5,369
Comprehensive loss attributable to noncontrolling interest	24	34	22
Comprehensive income (loss) attributable to Gilead	$ 6,368	$ (22)	$ 5,391