Market risk benefits (MRB Roll-Forward) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Market Risk Benefit [Line Items]
Market risk benefits gains (losses)		$ (142)	$ (230)	$ (251)	$ (238)
Long-Duration Insurance, Other | Variable Annuity
Market Risk Benefit [Line Items]
Balance - beginning of period				607	771
Balance, beginning of period, before effect of changes in the instrument-specific credit risk				592	749
Interest rate changes				45	10
Effect of market movements (1)	[1]			(115)	(147)
Effect of changes in volatilities				19	9
Actual policyholder behavior different from expected behavior				34	55
Effect of changes in future expected policyholder behavior		101	87	101	87
Effect of timing and all other				(29)	(34)
Balance, end of period, before effect of changes in the instrument-specific credit risk		647	729	647	729
Effect of changes in the instrument-specific credit risk		19	19	19	19
Balance - end of period		666	748	666	748
Market Risk Benefit, Net Amount at Risk	[2]	$ 1,385	$ 1,595	1,385	1,595
Market Risk Benefits Other Gains (Losses)				$ (197)	$ (258)
Weighted-average age of policyholders (years)				74 years	74 years

[1] Market movements are predominantly driven by changes in equities.

[2] The net amount at risk is defined as the present value of future claim payments assuming policy account values and guaranteed values are fixed at the valuation date, and reinsurance coverage ends at the earlier of the maturity of the underlying variable annuity policy or the reinsurance treaty. No withdrawals, lapses, and mortality improvements are assumed in the projection. GLB-related risks contain conservative mortality and annuitization assumptions.