Long-duration insurance contracts - Summary of life, annuity and health insurance benefits liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Life, annuity and health insurance benefits	$ 20,213	$ 19,753	$ 27,295
Periodic Payment Annuities [Member]
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Life, annuity and health insurance benefits	11,212	10,640	16,153
Life and Health [Member]
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Life, annuity and health insurance benefits	5,749	5,879	7,688
Other liabilities [Member]
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Life, annuity and health insurance benefits	$ 3,252	$ 3,234	$ 3,454