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Investments - Neumora Therapeutics, Inc. (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]
Equity securities	$ 3,985		$ 4,514
Unrealized gain (loss) on equity securities	$ 50	$ 5
Neumora Therapeutics, Inc.
Schedule of Equity Method Investments [Line Items]
Ownership percentage	22.30%		23.20%
Equity securities	$ 486		$ 603
Unrealized gain (loss) on equity securities	$ (117)	$ (47)
Neumora Therapeutics, Inc. \| Maximum
Schedule of Equity Method Investments [Line Items]
Ownership percentage		5.00%
Neumora Therapeutics, Inc. \| Minimum
Schedule of Equity Method Investments [Line Items]
Ownership percentage		10.00%