Insurance - Reinsurance information table including assumed, ceded, and recoveries (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Insurance [Abstract]
Direct premiums written	$ 9,933	$ 9,309	$ 8,774
Reinsurance assumed	600	347	283
Reinsurance ceded	(3,394)	(2,964)	(2,851)
Net written premiums	7,139	6,692	6,206
Direct premiums earned	9,763	9,133	8,582
Reinsurance assumed	611	321	274
Reinsurance ceded	(3,338)	(2,923)	(2,771)
Net earned premiums	7,036	6,531	6,085
Reinsurance recoveries	$ 3,040	$ 2,336	$ 2,065

Amount of earned premiums assumed from other entities.

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Amount of written premiums assumed from other entities.

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Amount of earned premiums ceded to other entities.

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Amount of written premiums ceded to other entities.

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Amount, before premiums ceded to other entities and premiums assumed by the entity, of premiums earned.

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Amount, before premiums ceded to other entities and premiums assumed by the entity, of premiums written.

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Amount, after premiums ceded to other entities and premiums assumed by the entity, of premiums earned.

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Amount, after premiums ceded to other entities and premiums assumed by the entity, of premiums written.

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Amount of reduction of provision for policy benefits and costs incurred for policies ceded.

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