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Investments - Neumora Therapeutics, Inc. (Details) - USD ($)	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Schedule of Equity Method Investments [Line Items]
Equity securities	$ 5,482,000,000		$ 4,188,000,000
Unrealized gains (losses) on equity securities	$ 0	$ 0
Neumora Therapeutics, Inc.
Schedule of Equity Method Investments [Line Items]
Ownership percentage	21.80%		21.90%
Equity securities	$ 35,000,000		$ 375,000,000
Unrealized gains (losses) on equity securities	$ (340,000,000)	$ (117,000,000)
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%