Future Contract Benefit - Summary of Gross Premiums and Interest Accretion (Group Protection) (Details) - Group Protection - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Liability for Future Policy Benefit, Activity [Line Items]
Gross premiums	$ 933	$ 896
Interest accretion	$ 50	$ 48

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details