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Long-duration insurance contracts - Summary of gross premiums earned and net interest expense (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Periodic Payment Annuity [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Net Interest Expense	$ 411	$ 402
Life and Health [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	2,831	2,587
Net Interest Expense	$ 100	$ 163

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- Definition

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