10-Q Business Optimization Initiatives (Employee Termination Costs) (Details) - Employee Termination [Member] - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Business Optimization Initiatives [Line Items]
Releases		$ (2)
2020 Business Optimization Initiatives
Business Optimization Initiatives [Line Items]
Liability for employee termination costs	$ 81	122
Payments	(32)	(39)
Releases	(33)	(2)
Liability for employee termination costs	16	81
2023-2024 Business Efficiency Program
Business Optimization Initiatives [Line Items]
Liability for employee termination costs	0
Payments and releases	0
Liability for employee termination costs	230	0
Health Benefits Segment | 2020 Business Optimization Initiatives
Business Optimization Initiatives [Line Items]
Liability for employee termination costs	80	118
Payments	(31)	(38)
Releases	(33)	0
Liability for employee termination costs	16	80
Health Benefits Segment | 2023-2024 Business Efficiency Program
Business Optimization Initiatives [Line Items]
Liability for employee termination costs	0
Payments and releases	0
Liability for employee termination costs	0	0
CarelonRx Segment [Member] | 2020 Business Optimization Initiatives
Business Optimization Initiatives [Line Items]
Liability for employee termination costs	1	1
Payments	(1)	0
Releases	0	0
Liability for employee termination costs	0	1
CarelonRx Segment [Member] | 2023-2024 Business Efficiency Program
Business Optimization Initiatives [Line Items]
Liability for employee termination costs	0
Payments and releases	0
Liability for employee termination costs	0	0
Carelon Services Segment | 2020 Business Optimization Initiatives
Business Optimization Initiatives [Line Items]
Liability for employee termination costs	0	0
Payments	0	0
Releases	0	0
Liability for employee termination costs	0	0
Carelon Services Segment | 2023-2024 Business Efficiency Program
Business Optimization Initiatives [Line Items]
Liability for employee termination costs	0
Payments and releases	0
Liability for employee termination costs	0	0
Other [Member] | 2020 Business Optimization Initiatives
Business Optimization Initiatives [Line Items]
Liability for employee termination costs	0	3
Payments	0	(1)
Releases	0	(2)
Liability for employee termination costs	0	0
Other [Member] | 2023-2024 Business Efficiency Program
Business Optimization Initiatives [Line Items]
Liability for employee termination costs	0
Payments and releases	0
Liability for employee termination costs	$ 230	$ 0