Financial Instruments - Available-for-sale Marketable Securities (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Marketable Securities [Line Items]
Less than 12 months, fair value	$ 1,767	$ 1,054
Less than 12 months, unrealized losses	(3)	(4)
12 months or greater, fair value	14,182	20,391
12 months or greater, unrealized losses	(398)	(930)
Fair value	15,949	21,445
Unrealized losses	(401)	(934)
U.S. government securities
Marketable Securities [Line Items]
Less than 12 months, fair value	1,140	336
Less than 12 months, unrealized losses	(2)	(1)
12 months or greater, fair value	4,744	7,041
12 months or greater, unrealized losses	(126)	(275)
Fair value	5,884	7,377
Unrealized losses	(128)	(276)
U.S. government and agency securities
Marketable Securities [Line Items]
Less than 12 months, fair value	123	71
Less than 12 months, unrealized losses	0	0
12 months or greater, fair value	2,407	3,225
12 months or greater, unrealized losses	(63)	(164)
Fair value	2,530	3,296
Unrealized losses	(63)	(164)
Corporate debt securities
Marketable Securities [Line Items]
Less than 12 months, fair value	504	647
Less than 12 months, unrealized losses	(1)	(3)
12 months or greater, fair value	7,031	10,125
12 months or greater, unrealized losses	(209)	(491)
Fair value	7,535	10,772
Unrealized losses	$ (210)	$ (494)