Policyholders' account balances (Policyholder Account Balance Rollforward) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jul. 01, 2023	Dec. 31, 2020
Policyholder Account Balance [Line Items]
Balance – beginning of period		$ 2,573	$ 2,263	$ 2,165
Policyholder Account Balance, Acquisition of Cigna		4,014	355
Policyholder Account Balance, Premium Received		632	333	348
Policyholder Account Balance, Policy Charge	[1]	(142)	(151)	(156)
Policyholder Account Balance, Surrender and Withdrawal		(326)	(134)	(117)
Policyholder Account Balance, Benefit Payment	[2]	(132)	(33)	(43)
Policyholder Account Balance, Interest Expense		113	47	49
Policyholder Account Balance, Increase (Decrease) from Other Change		57	107	(17)
Balance – end of period		6,789	2,573	2,263
Unearned revenue liability		673	567	503		$ 393
Policyholders' account balances		7,462	3,140	2,766
Huatai Group [Member]
Policyholder Account Balance [Line Items]
Policyholders' account balances					$ 4,014
Universal Life
Policyholder Account Balance [Line Items]
Balance – beginning of period		1,199	875	813
Policyholder Account Balance, Premium Received		268	232	228
Policyholder Account Balance, Policy Charge	[1]	(132)	(136)	(138)
Policyholder Account Balance, Surrender and Withdrawal		(115)	(50)	(51)
Policyholder Account Balance, Benefit Payment	[2]	(12)	(6)	(17)
Policyholder Account Balance, Interest Expense		43	27	27
Policyholder Account Balance, Increase (Decrease) from Other Change		23	91	(13)
Balance – end of period		1,876	1,199	875
Policyholders' account balances		$ 1,876	$ 1,199	$ 875
Policyholder Account Balance, Weighted Average Crediting Rate		3.00%	2.50%	3.40%
Policyholder Account Balance, Net Amount at Risk	[3]	$ 11,828	$ 11,472	$ 10,749
Policyholder Account Balance, Cash Surrender Value		1,628	1,001	680
Universal Life | Cigna's Life Insurance Business in Asian Markets
Policyholder Account Balance [Line Items]
Policyholder Account Balance, Acquisition of Cigna			348
Universal Life | Huatai Group [Member]
Policyholder Account Balance [Line Items]
Policyholder Account Balance, Acquisition of Cigna		602
Annuities [Member]
Policyholder Account Balance [Line Items]
Balance – beginning of period	[4]	0
Policyholder Account Balance, Premium Received	[4]	133
Policyholder Account Balance, Policy Charge	[1],[4]	0
Policyholder Account Balance, Surrender and Withdrawal	[4]	(19)
Policyholder Account Balance, Benefit Payment	[2],[4]	(58)
Policyholder Account Balance, Interest Expense	[4]	31
Policyholder Account Balance, Increase (Decrease) from Other Change	[4]	(1)
Balance – end of period	[4]	2,411	0
Policyholders' account balances		$ 2,411
Policyholder Account Balance, Weighted Average Crediting Rate		2.60%
Policyholder Account Balance, Net Amount at Risk	[3]	$ 0
Policyholder Account Balance, Cash Surrender Value		1,526
Annuities [Member] | Huatai Group [Member]
Policyholder Account Balance [Line Items]
Policyholder Account Balance, Acquisition of Cigna	[4]	2,325
Insurance, Other [Member]
Policyholder Account Balance [Line Items]
Balance – beginning of period	[5]	1,374	1,388	1,352
Policyholder Account Balance, Premium Received	[5]	231	101	120
Policyholder Account Balance, Policy Charge	[1],[5]	(10)	(15)	(18)
Policyholder Account Balance, Surrender and Withdrawal	[5]	(192)	(84)	(66)
Policyholder Account Balance, Benefit Payment	[2],[5]	(62)	(27)	(26)
Policyholder Account Balance, Interest Expense	[5]	39	20	22
Policyholder Account Balance, Increase (Decrease) from Other Change	[5]	35	16	(4)
Balance – end of period	[5]	2,502	1,374	1,388
Policyholders' account balances		$ 2,502	$ 1,374	$ 1,388
Policyholder Account Balance, Weighted Average Crediting Rate		1.90%	1.70%	1.90%
Policyholder Account Balance, Net Amount at Risk	[3]	$ 559	$ 182	$ 180
Policyholder Account Balance, Cash Surrender Value		2,192	1,257	$ 1,247
Insurance, Other [Member] | Cigna's Life Insurance Business in Asian Markets
Policyholder Account Balance [Line Items]
Policyholder Account Balance, Acquisition of Cigna	[5]		$ 7
Insurance, Other [Member] | Huatai Group [Member]
Policyholder Account Balance [Line Items]
Policyholder Account Balance, Acquisition of Cigna	[5]	$ 1,087

[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] 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.

[4] Relates to Huatai Life.

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