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Long-duration insurance contracts - Summary of changes in discounted present values of expected future policy benefits and expected future net premiums (Detail) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2024 | Mar. 31, 2023
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward] |  |
Balance at March 31 | $ 17,987 | $ 19,937
Periodic Payment Annuity [Member] |  |
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward] |  |
Balance at beginning of year | 11,212 | 10,640
Balance at beginning of year at original discount rate | 11,681 | 11,549
Effect of actual versus expected experience | 2 | 1
Change in benefits, net | (115) | (116)
Interest accrual | 136 | 133
Foreign currency effect | 2 | 19
Ending balance at original discount rate | 11,706 | 11,586
Effect of changes in discount rate assumptions | (957) | (412)
Expected future policy benefits at March 31 | 10,749 | 11,174
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward] |  |
Balance at March 31 | 10,749 | 11,174
Liabilities for future policy benefits at March 31, net of reinsurance recoverables | 10,749 | 11,174
Life and Health [Member] |  |
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward] |  |
Balance at beginning of year | 52,665 | 52,008
Balance at beginning of year at original discount rate | 65,871 | 63,584
Effect of cash flow assumption changes | (34) | (1)
Effect of actual versus expected experience | (12,870) | (519)
Change in benefits, net | (449) | (747)
Interest accrual | 284 | 425
Foreign currency effect | (389) | 47
Ending balance at original discount rate | 52,413 | 62,789
Effect of changes in discount rate assumptions | (11,627) | (12,169)
Expected future policy benefits at March 31 | 40,786 | 50,620
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward] |  |
Balance at beginning of year | 46,916 | 46,129
Balance at beginning of year at original discount rate | 58,731 | 56,535
Effect of cash flow assumption changes | (25) | 2
Effect of actual versus expected experience | (11,278) | (413)
Change in premiums, net | (407) | (660)
Interest accrual | 251 | 371
Foreign currency effect | (358) | 47
Ending balance at original discount rate | 46,914 | 55,882
Effect of changes in discount rate assumptions | (10,387) | (10,895)
Expected future net premiums at March 31 | 36,527 | 44,987
Balance at March 31 | 4,259 | 5,633
Reinsurance recoverables | (50) | (1,565)
Liabilities for future policy benefits at March 31, net of reinsurance recoverables | $ 4,209 | $ 4,068

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