Fair Value of Financial Instruments - Investments Held at Net Asset Value (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Fair value disclosure
Gain (loss) on investments	$ 20	$ (61)
Net Asset Value \| Fair Value
Fair value disclosure
Investment in limited partnership	$ 30		$ 10

Fair value of investment in security owned.

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+ Details