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	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Abstract]
Favorable (unfavorable) variance, amount	$ 284	$ 202
Favorable (unfavorable) variance, percentage	0.80%	0.60%
Actual completion factors
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Abstract]
Favorable (unfavorable) variance, amount	$ 83	$ 29
Favorable (unfavorable) variance, percentage	0.20%	0.10%
Medical cost trend
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Abstract]
Favorable (unfavorable) variance, amount	$ 201	$ 173
Favorable (unfavorable) variance, percentage	0.60%	0.50%