Insurance and Contractholder Liabilities - Unpaid Claims and Claims Expenses - Cigna Healthcare - Variances in Incurred Costs Related to Prior Years' Unpaid Claims and Claims Expenses (Details) - Cigna Healthcare - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Abstract]
Favorable (unfavorable) variance, amount	$ 422	$ 237
Favorable (unfavorable) variance, percentage	1.20%	0.80%
Actual completion factors and other
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Abstract]
Favorable (unfavorable) variance, amount	$ 212	$ 45
Favorable (unfavorable) variance, percentage	0.60%	0.20%
Medical cost trend
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Abstract]
Favorable (unfavorable) variance, amount	$ 210	$ 192
Favorable (unfavorable) variance, percentage	0.60%	0.60%