Insurance and Contractholder Liabilities - Future Policy Benefits - Present Value of Expected Premiums and Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Observable inputs from published spot rate curve term (in years)	30 years
Percent of the liability for future policy benefits supported by assets held in trust	34.00%
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	8,557	$ 9,314
Reversal of effect of beginning of period discount rate assumptions	1,537	(367)
Effect of assumption changes and actual variances from expected experience (1)		314	$ 1,286
Issuances and lapses	1,255	1,067
Net premiums collected	(1,370)	(1,280)
Interest and other	94	74
Ending balance at original discount rate	10,387	10,094
Effect of end of period discount rate assumptions	(1,154)	(1,537)
Ending balance	9,233	8,557	9,314
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Beginning balance	8,945	9,794
Reversal of effect of discount rate assumptions	1,611	(379)
Effect of assumption changes and actual variances from expected experience (1)		112	1,148
Issuances and lapses	1,309	1,176
Benefit payments	(1,374)	(1,401)
Interest and other	250	218
Ending balance at original discount rate	10,853	10,556
Effect of discount rate assumptions	(1,220)	(1,611)
Ending balance	9,633	8,945	9,794
Liability for future policy benefits	400	388
Other	215	199
Total liability for future policy benefits		587
Total liability for future policy benefits, including assets held for sale	615
Effect of actual variances from expectations	(12)	46
Undiscounted expected future gross premiums	18,700	17,500
Discounted expected future gross premiums	13,500	12,200
Undiscounted expected future policy benefits	13,300	12,700
Future policy benefits reserve, reinsurance recoverables	72	155
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	79
Other Operations
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Total liability for future policy benefits	3,538	3,592
Undiscounted expected future policy benefits	4,500	4,600
Future policy benefits reserve, reinsurance recoverables	1,000	1,100
Future policy benefits, DPL	384	390
Future policy benefit, excluding DPL	$ 3,200	$ 3,200	4,300
Other Operations | Disposed of by Sale | International life, accident and supplemental benefits businesses
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Future policy benefits classified as liabilities of business held for sale			$ 3,800