Financial Instruments - Investments - Unrealized Gains and Losses Related to Equity Securities (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023		Dec. 31, 2022		Dec. 31, 2021
Fair Value Disclosures [Abstract]
Net (gains)/losses recognized during the period on equity securities	[1]	$ (1,590)	[2]	$ 1,273	[2]	$ (1,344)
Less: Net (gains)/losses recognized during the period on equity securities sold during the period		(1,754)		(126)		(80)
Net unrealized (gains)/losses during the reporting period on equity securities still held at the reporting date	[3]	$ 165		$ 1,400		$ (1,264)

[1] (c)2023 net gains primarily include, among other things, a realized gain of $1.7 billion related to our investment in Telavant Holdings, Inc. and unrealized gains of $297 million related to our investment in Cerevel Therapeutics Holdings, Inc (Cerevel), partially offset by unrealized losses of $292 million related to our investment in BioNTech. 2022 net losses included, among other things, unrealized losses of $986 million related to investments in BioNTech, Allogene Therapeutics, Inc. and Arvinas. 2021 net gains included, among other things, unrealized gains of $1.6 billion related to investments in BioNTech and Cerevel.

[2] Reported in Other (income)/deductions––net. See Note 4.

[3] Included in net unrealized (gains)/losses are observable price changes on equity securities without readily determinable fair values. As of December 31, 2023, there were cumulative impairments and downward adjustments of $259 million and upward adjustments of $213 million. Impairments, downward and upward adjustments were not material to our operations in 2023, 2022 and 2021