Policyholders' account balances (Policyholder Account Balance Rollforward) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Jul. 01, 2023	Dec. 31, 2022
Policyholder Account Balance [Line Items]
Balance – beginning of period		$ 6,789	$ 2,573
Policyholder Account Balance, Acquisition			4,014
Policyholder Account Balance, Premium Received		1,028	632
Policyholder Account Balance, Policy Charge	[1]	(147)	(142)
Policyholder Account Balance, Surrender and Withdrawal		(439)	(326)
Policyholder Account Balance, Benefit Payment	[2]	(277)	(132)
Policyholder Account Balance, Interest Expense		159	113
Policyholder Account Balance, Increase (Decrease) from Other Change		(365)	(57)
Balance – end of period		6,748	6,789
Unearned revenue liability		711	673		$ 567
Policyholder Account Balance, Other Reconciling Items	[3]	557
Policyholders' account balances		8,016	7,462
Huatai Group [Member]
Policyholder Account Balance [Line Items]
Policyholders' account balances				$ 4,014
Universal Life
Policyholder Account Balance [Line Items]
Balance – beginning of period		1,876	1,199
Policyholder Account Balance, Acquisition			602
Policyholder Account Balance, Premium Received		276	268
Policyholder Account Balance, Policy Charge	[1]	(136)	(132)
Policyholder Account Balance, Surrender and Withdrawal		(122)	(115)
Policyholder Account Balance, Benefit Payment	[2]	(60)	(12)
Policyholder Account Balance, Interest Expense		50	43
Policyholder Account Balance, Increase (Decrease) from Other Change		(75)	(23)
Balance – end of period		1,809	1,876
Policyholders' account balances		$ 1,809	$ 1,876
Policyholder Account Balance, Weighted Average Crediting Rate	[4]	2.80%	3.00%
Policyholder Account Balance, Net Amount at Risk	[5]	$ 12,369	$ 11,828
Policyholder Account Balance, Cash Surrender Value		1,649	1,628
Annuities [Member]
Policyholder Account Balance [Line Items]
Balance – beginning of period	[6]	2,411	0
Policyholder Account Balance, Acquisition	[6]		2,325
Policyholder Account Balance, Premium Received	[6]	339	133
Policyholder Account Balance, Policy Charge	[1],[6]	0	0
Policyholder Account Balance, Surrender and Withdrawal	[6]	(39)	(19)
Policyholder Account Balance, Benefit Payment	[2],[6]	(139)	(58)
Policyholder Account Balance, Interest Expense	[6]	41	31
Policyholder Account Balance, Increase (Decrease) from Other Change	[6]	(28)	(1)
Balance – end of period	[6]	2,585	2,411
Policyholders' account balances		$ 2,585	$ 2,411
Policyholder Account Balance, Weighted Average Crediting Rate	[4]	1.70%	2.60%
Policyholder Account Balance, Net Amount at Risk	[5]	$ 0	$ 0
Policyholder Account Balance, Cash Surrender Value		1,678	1,526
Insurance, Other [Member]
Policyholder Account Balance [Line Items]
Balance – beginning of period	[7]	2,502	1,374
Policyholder Account Balance, Acquisition	[7]		1,087
Policyholder Account Balance, Premium Received	[7]	413	231
Policyholder Account Balance, Policy Charge	[1],[7]	(11)	(10)
Policyholder Account Balance, Surrender and Withdrawal	[7]	(278)	(192)
Policyholder Account Balance, Benefit Payment	[2],[7]	(78)	(62)
Policyholder Account Balance, Interest Expense	[7]	68	39
Policyholder Account Balance, Increase (Decrease) from Other Change	[7]	(262)	(35)
Balance – end of period	[7]	2,354	2,502
Policyholders' account balances		$ 2,354	$ 2,502
Policyholder Account Balance, Weighted Average Crediting Rate	[4]	3.00%	1.90%
Policyholder Account Balance, Net Amount at Risk	[5]	$ 425	$ 559
Policyholder Account Balance, Cash Surrender Value		$ 2,060	$ 2,192

[1] Contracts included in the policyholder account balances are generally charged a premium and/or monthly assessments on the basis of the account balance.

[2] Includes benefit payments upon maturity as well as death benefits.

[3] Primarily comprises unpaid dividends on certain participating policies.

[4] Calculated using actual interest credited for the twelve months ended December 31, 2024 and 2023, respectively.

[5] For those guarantees of benefits that are payable in the event of death, the net amount at risk is defined as the current guaranteed minimum death benefit in excess of the current account balance at the balance sheet date.

[6] Relates to Huatai Life.

[7] Primarily comprises policyholder account balances related to investment linked products including endowment and investment contracts, none of which bear significant insurance risk.