Separate accounts (Separate account liabilities rollforward) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Separate Account, Liability [Line Items]
Separate Account, Liability, Beginning Balance		$ 5,190	$ 5,560	$ 4,488
Acquisition of Cigna		0		0
Separate Account, Liability, Premium and Deposit		995	1,453	2,086
Separate Account, Liability, Policy Charge		(138)	(127)	(128)
Separate Account, Liability, Surrender and Withdrawal		(601)	(503)	(720)
Separate Account, Liability, Benefit Payment		(381)	(381)	(318)
Separate Account, Liability, Increase (Decrease) from Invested Performance		611	(848)	312
Separate Account, Liability, Increase (Decrease) from Other Change		(103)	(265)	(160)
Separate Account, Liability, Ending Balance		5,573	5,190	5,560
Separate Account, Liability, Cash Surrender Value, Amount	[1]	$ 5,398	4,989	$ 5,309
Cigna's Life Insurance Business in Asian Markets
Separate Account, Liability [Line Items]
Acquisition of Cigna			$ 301

[1] Cash surrender value represents the amount of the contract holder's account balances distributable at the balance sheet date less certain surrender charges