Insurance and Contractholder Liabilities - Unpaid Claims and Claim Expenses - Cigna Healthcare - Activity (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024	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		$ 1,378	$ 983	$ 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 and reported claims in process	$ 4,400	5,400
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Beginning balance, including held for sale liabilities	5,018	5,092
Less: Reinsurance, including held for sale liabilities	159	236
Beginning balance, net, including held for sale liabilities	4,859	4,856
Incurred costs related to:
Current year	10,606	9,452
Prior years	(222)	(226)
Total incurred	10,384	9,226
Paid costs related to:
Current year	6,078	5,072
Prior years	3,472	3,352
Total paid	9,550	8,424
Less: Divestiture and other	1,323	0
Ending balance, net	4,370
Add: Reinsurance and other amounts recoverable	138
Ending balance	$ 4,508
Ending balance, net, including held for sale liabilities		5,658
Add: Reinsurance, including held for sale liabilities		205
Ending balance, including held for sale liabilities		$ 5,863