Long-duration insurance contracts - Summary of gross premiums earned and net interest expense (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Periodic Payment Annuity [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Net Interest Expense	$ 557	$ 550
Life and Health [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	3,994	3,830
Net Interest Expense	$ 135	$ 135

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