Insurance and Contractholder Liabilities - Unpaid Claims and Claim Expenses - Cigna Healthcare - Activity (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Held-for-Sale | Medicare Advantage and related Cigna Healthcare businesses
Paid costs related to:
Unpaid claims classified as liabilities of business held for sale	$ 900		$ 823
Cigna Healthcare
Liability for Claims and Claims Adjustment Expense [Line Items]
Total of incurred but not reported liabilities plus expected claim development on reported claims, including reported claims in process	4,800	$ 5,000
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Beginning balance		4,176
Less: Reinsurance and other amounts recoverable		221
Beginning balance, net		3,955
Beginning balance, including held for sale liabilities	5,092
Less: Reinsurance, including held for sale liabilities	236
Beginning balance, net, including held for sale liabilities	4,856
Incurred costs related to:
Current year	18,821	17,974
Prior years	(284)	(202)
Total incurred	18,537	17,772
Paid costs related to:
Current year	14,397	13,408
Prior years	3,960	3,199
Total paid	18,357	16,607
Ending balance, net		5,120
Add: Reinsurance and other amounts recoverable		216
Ending balance		$ 5,336
Ending balance, net, including held for sale liabilities	5,036
Add: Reinsurance, including held for sale liabilities	166
Ending balance, including held for sale liabilities	$ 5,202