10-Q Business Optimization Initiatives (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Business Optimization Initiatives [Line Items]
Business optimization initiatives, incurred cost	$ 730		$ 39	$ 202	$ 653
Business Optimization, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Operating expense		Operating expense	Operating expense	Operating expense
Health Benefits Segment
Business Optimization Initiatives [Line Items]
Business optimization initiatives, incurred cost			$ 36	$ 168	$ 516
CarelonRx Segment [Member]
Business Optimization Initiatives [Line Items]
Business optimization initiatives, incurred cost			0	1	4
Carelon Services Segment
Business Optimization Initiatives [Line Items]
Business optimization initiatives, incurred cost			5	33	122
Other [Member]
Business Optimization Initiatives [Line Items]
Business optimization initiatives, incurred cost			2	$ 0	11
Employee Termination [Member]
Business Optimization Initiatives [Line Items]
Business optimization initiatives, incurred cost					$ 197
Releases			(2)
2023-2024 Business Efficiency Program | Employee Termination [Member]
Business Optimization Initiatives [Line Items]
Business optimization initiatives, incurred cost	$ 230
Restructuring Reserve, Period Increase (Decrease)		$ 0
Restructuring Charges		230
2023-2024 Business Efficiency Program | Employee Termination [Member] | Health Benefits Segment
Business Optimization Initiatives [Line Items]
Restructuring Reserve, Period Increase (Decrease)		0
Restructuring Charges		0
2023-2024 Business Efficiency Program | Employee Termination [Member] | CarelonRx Segment [Member]
Business Optimization Initiatives [Line Items]
Restructuring Reserve, Period Increase (Decrease)		0
Restructuring Charges		0
2023-2024 Business Efficiency Program | Employee Termination [Member] | Carelon Services Segment
Business Optimization Initiatives [Line Items]
Restructuring Reserve, Period Increase (Decrease)		0
Restructuring Charges		0
2023-2024 Business Efficiency Program | Employee Termination [Member] | Other [Member]
Business Optimization Initiatives [Line Items]
Restructuring Reserve, Period Increase (Decrease)		0
Restructuring Charges		230
2023-2024 Business Efficiency Program | Information Technology Assets and Related Contract
Business Optimization Initiatives [Line Items]
Business optimization initiatives, incurred cost	446
2023-2024 Business Efficiency Program | Asset Impairments
Business Optimization Initiatives [Line Items]
Business optimization initiatives, incurred cost	$ 54
2020 Business Optimization Initiatives | Employee Termination [Member]
Business Optimization Initiatives [Line Items]
Releases		(33)	(2)
2020 Business Optimization Initiatives | Employee Termination [Member] | Health Benefits Segment
Business Optimization Initiatives [Line Items]
Releases		(33)	0
2020 Business Optimization Initiatives | Employee Termination [Member] | CarelonRx Segment [Member]
Business Optimization Initiatives [Line Items]
Releases		0	0
2020 Business Optimization Initiatives | Employee Termination [Member] | Carelon Services Segment
Business Optimization Initiatives [Line Items]
Releases		0	0
2020 Business Optimization Initiatives | Employee Termination [Member] | Other [Member]
Business Optimization Initiatives [Line Items]
Releases		$ 0	$ (2)