Insurance and Contractholder Liabilities - Contractholder Deposit Funds (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Insurance and Contractholder Liabilities [Line Items]
Contractholder deposit fund liabilities, approximate percent reinsured externally	38.00%
Cigna Healthcare
Insurance and Contractholder Liabilities [Line Items]
Contractholder deposit funds			$ 158
Other Operations
Insurance and Contractholder Liabilities [Line Items]
Contractholder deposit funds	$ 6,381	$ 6,540	$ 6,647	$ 6,700
Weighted average crediting rate	3.25%		3.26%
Net amount at risk	$ 2,900		$ 3,200
Cash surrender value	$ 2,800		$ 2,800
Other Operations | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 To 0400
Insurance and Contractholder Liabilities [Line Items]
Contractholder deposit funds not reinsured externally, percent with guaranteed interest rates of 0300 to 0400	99.00%		99.00%
Contractholder deposit funds not reinsured externally	$ 4,000		$ 4,100
Other Operations | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 To 0400 | Policyholder Account Balance, at Guaranteed Minimum Crediting Rate
Insurance and Contractholder Liabilities [Line Items]
Contractholder deposit funds not reinsured externally	1,100		1,200
Other Operations | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 To 0400 | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Insurance and Contractholder Liabilities [Line Items]
Contractholder deposit funds not reinsured externally	1,200		1,200
Other Operations | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 To 0400 | Policyholder Account Balance, Above Guaranteed Minimum Crediting Rate, Based On Greater Of Guaranteed Minimum Cash Value Or Actual Cash Value
Insurance and Contractholder Liabilities [Line Items]
Contractholder deposit funds not reinsured externally	$ 1,700		$ 1,700
Percentage with cash values at more than 110% of guaranteed cash value	90.00%		90.00%
Other Operations | Minimum | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Insurance and Contractholder Liabilities [Line Items]
Basis points above guaranteed minimum crediting rate	0.0050		0.0050
Other Operations | Minimum | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 To 0400
Insurance and Contractholder Liabilities [Line Items]
Guaranteed minimum credit rating	3.00%		3.00%
Other Operations | Maximum | Policyholder Account Balance, above Guaranteed Minimum Crediting Rate, Range from 0051 to 0150
Insurance and Contractholder Liabilities [Line Items]
Basis points above guaranteed minimum crediting rate	0.0150		0.0150
Other Operations | Maximum | Policyholder Account Balance, Guaranteed Minimum Crediting Rate, Range from 0300 To 0400
Insurance and Contractholder Liabilities [Line Items]
Guaranteed minimum credit rating	4.00%		4.00%