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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 | 6 Months Ended
--- | ---
Jun. 30, 2024 | Jun. 30, 2023
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward] |  |
Balance at June 30 | $ 17,500 | $ 19,635
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 | 4 | 2
Change in benefits, net | (235) | (230)
Interest accrual | 273 | 266
Foreign currency effect | 15 | 83
Ending balance at original discount rate | 11,738 | 11,670
Effect of changes in discount rate assumptions | (1,360) | (850)
Expected future policy benefits at June 30 | 10,378 | 10,820
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward] |  |
Balance at June 30 | 10,378 | 10,820
Liabilities for future policy benefits at June 30, net of reinsurance recoverables | 10,378 | 10,820
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 | (324) | 10
Effect of actual versus expected experience | (12,836) | (411)
Change in benefits, net | (943) | (1,346)
Interest accrual | 575 | 852
Foreign currency effect | (459) | 100
Ending balance at original discount rate | 51,884 | 62,789
Effect of changes in discount rate assumptions | (12,739) | (12,741)
Expected future policy benefits at June 30 | 39,145 | 50,048
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 | (326) | 18
Effect of actual versus expected experience | (11,225) | (251)
Change in premiums, net | (876) | (1,222)
Interest accrual | 507 | 745
Foreign currency effect | (436) | 83
Ending balance at original discount rate | 46,375 | 55,908
Effect of changes in discount rate assumptions | (11,397) | (11,383)
Expected future net premiums at June 30 | 34,978 | 44,525
Balance at June 30 | 4,167 | 5,523
Reinsurance recoverables | (49) | (1,549)
Liabilities for future policy benefits at June 30, net of reinsurance recoverables | $ 4,118 | $ 3,974

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