Insurance and Contractholder Liabilities - Future Policy Benefits - Present Value of Expected Premiums and Benefits (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
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			$ 429
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
Issuances and lapses	446	306
Net premiums collected	(350)	(326)
Interest and other	73	56
Ending balance at original discount rate	10,556	10,130
Effect of end of period discount rate assumptions	(1,309)	(1,312)
Ending balance	9,247	8,818	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
Issuances and lapses	457	307
Benefit payments	(362)	(326)
Interest and other	71	58
Ending balance at original discount rate	11,019	10,595
Effect of discount rate assumptions	(1,381)	(1,378)
Ending balance	9,638	9,217	9,633	8,945
Liability for future policy benefits	391	399
Other	216	202
Total liability for future policy benefits		601
Total liability for future policy benefits, including assets held for sale	607
Undiscounted expected future gross premiums	19,000	17,600
Discounted expected future gross premiums	13,300	12,500
Undiscounted expected future policy benefits	13,600	12,800
Future policy benefits reserve, reinsurance recoverables	72	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 reserve, reinsurance recoverables reported in assets of businesses held for sale	81
Future policy benefits classified as liabilities of business held for sale	427
Other Operations
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Total liability for future policy benefits	3,460	3,631	3,538
Undiscounted expected future policy benefits	4,400	4,600
Future policy benefits reserve, reinsurance recoverables	1,000	1,000
Future policy benefits, DPL	379	392
Future policy benefit, excluding DPL	$ 3,100	$ 3,200	$ 3,200	$ 3,200