Insurance and Contractholder Liabilities - Future Policy Benefits - Present Value of Expected Premiums and Benefits (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Cigna Healthcare
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]
Beginning balance	$ 9,233	$ 8,557
Reversal of effect of beginning of period discount rate assumptions	1,154	1,537
Effect of assumption changes and actual variances from expected experience (2)			$ (90)	$ 51
Issuances and lapses	848	570
Net premiums collected	(699)	(658)
Interest and other	142	106
Ending balance at original discount rate	10,588	10,163
Effect of end of period discount rate assumptions	(1,357)	(1,491)
Ending balance	9,231	8,672	9,233	8,557
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	9,633	8,945
Reversal of effect of discount rate assumptions	1,220	1,611
Effect of assumption changes and actual variances from expected experience (2)			(87)	54
Issuances and lapses	855	558
Benefit payments	(725)	(661)
Interest and other	147	121
Ending balance at original discount rate	11,043	10,628
Effect of discount rate assumptions	(1,432)	(1,565)
Ending balance	9,611	9,063	9,633	8,945
Liability for future policy benefits	380	391
Other	216	204
Total liability for future policy benefits		595
Total liability for future policy benefits, including assets held for sale	596
Effect of actual variances from expectations	(2)	2
Undiscounted expected future gross premiums	18,900	17,700
Discounted expected future gross premiums	13,200	12,300
Undiscounted expected future policy benefits	13,700	12,900
Future policy benefits reserve, reinsurance recoverables	73	154
Cigna Healthcare | Held-for-Sale | Medicare Advantage and related Cigna Healthcare businesses
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Future policy benefits classified as liabilities of business held for sale	417		429
Future policy benefits reserve, reinsurance recoverables reported in assets of businesses held for sale	80
Other Operations
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Total liability for future policy benefits	3,362	3,587	3,538
Undiscounted expected future policy benefits	4,400	4,500
Future policy benefits reserve, reinsurance recoverables	900	1,000
Future policy benefits, DPL	400	400
Future policy benefit, excluding DPL	$ 3,000	$ 3,200	$ 3,200	$ 3,200