Market risk benefits (MRB Roll-Forward) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2025	Mar. 31, 2024
Market Risk Benefit [Line Items]
Market risk benefits gains (losses)		$ (92)	$ 21
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		46	(57)
Effect of market movements (1)	[1]	52	(77)
Effect of changes in volatilities		16	(20)
Market Risk Benefit, Increase (Decrease) from Actual Policyholder Behavior Different from Expected		16	30
Effect of timing and all other		(25)	(31)
Balance, end of period, before effect of changes in the instrument-specific credit risk		697	594
Effect of changes in the instrument-specific credit risk		11	17
Balance - end of period		708	611
Market Risk Benefit, Net Amount at Risk	[2]	1,654	1,683
Market Risk Benefits Other Gains (Losses)		$ 14	$ (134)
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.