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	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Abstract]
Favorable (unfavorable) variance, amount	$ 226	$ 144
Favorable (unfavorable) variance, percentage	0.60%	0.50%
Actual completion factors
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Abstract]
Favorable (unfavorable) variance, amount	$ 76	$ 1
Favorable (unfavorable) variance, percentage	0.20%	0.00%
Medical cost trend
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Abstract]
Favorable (unfavorable) variance, amount	$ 150	$ 143
Favorable (unfavorable) variance, percentage	0.40%	0.50%