Long-duration insurance contracts - Summary of Other Information Relating to Long-Duration Insurance Liabilities (Detail) - USD ($) $ in Millions |
Jun. 30, 2025 |
Jun. 30, 2024 |
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| Periodic Payment Annuity [Member] | ||
| Liability for Future Policy Benefit, Activity [Line Items] | ||
| Undiscounted expected future benefits | $ 30,670 | $ 30,867 |
| Weighted average discount rate | 5.70% | 5.70% |
| Weighted average accretion rate | 4.80% | 4.80% |
| Weighted average duration (in years) | 16 years | 16 years |
| Life and Health [Member] | ||
| Liability for Future Policy Benefit, Activity [Line Items] | ||
| Undiscounted expected future gross premiums | $ 103,580 | $ 94,942 |
| Discounted expected future gross premiums | 60,951 | 55,787 |
| Undiscounted expected future benefits | $ 94,173 | $ 86,253 |
| Weighted average discount rate | 5.20% | 5.20% |
| Weighted average accretion rate | 2.70% | 2.70% |
| Weighted average duration (in years) | 13 years | 13 years |
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- Definition 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. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Current weighted-average discount rate used to measure liability for future policy benefit. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount, before effect of reinsurance, of discounted balance for expected future gross premium component of liability for future policy benefit. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount, before effect of reinsurance, of undiscounted balance for expected future gross premium component of liability for future policy benefit. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount, before effect of reinsurance, of undiscounted balance for expected future policy benefit and expense component of liability for future policy benefit. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Weighted-average duration of liability for future policy benefit, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Original weighted-average discount rate at contract issue date used to measure liability for future policy benefit. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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