Market risk benefits (MRB Roll-Forward) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Market Risk Benefit [Line Items]
Market Risk Benefit, Liability, beginning of period				$ 771
Market Risk Benefit, Liability, end of period		$ 748		748
Market risk benefits gains (losses)		(230)	$ (32)	(238)	$ (154)
Long-Duration Insurance, Other | Variable Annuity
Market Risk Benefit [Line Items]
Market Risk Benefit, Liability, beginning of period				771	800
Balance, beginning of period, before effect of changes in the instrument-specific credit risk				749	776
Interest rate changes				10	(117)
Effect of changes in equity markets				(147)	(69)
Effect of changes in volatilities				9	51
Market Risk Benefit, Increase (Decrease) from Actual Policyholder Behavior Different from Expected				55	16
Market Risk Benefit, Increase (Decrease) from Future Expected Policyholder Behavior Assumption		87		87	89
Effect of timing and all other				(34)	3
Balance, end of period, before effect of changes in the instrument-specific credit risk		729	749	729	749
Effect of changes in the instrument-specific credit risk		19	21	19	21
Market Risk Benefit, Liability, end of period		748	770	748	770
Market Risk Benefit, Net Amount at Risk	[1]	$ 1,595	$ 2,138	1,595	2,138
Market Risk Benefits Other Gains (Losses)				$ (258)	$ (181)
Weighted-average age of policyholders (years)				74 years	73 years

[1] 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.