10-K Segment Information (Financial Data By Reportable Segment) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Premiums	$ 35,259	$ 33,722	$ 107,716	$ 99,583	$ 133,229	$ 117,373	$ 104,109
Product revenue	5,177	3,972	14,058	10,841	14,978	12,657	10,384
Service fees	2,044	1,931	5,981	5,569	7,453	6,913	6,315
Total operating revenue	42,480	39,625	127,755	115,993	155,660	136,943	120,808
Operating gain (loss)	1,756	2,251	7,215	7,024	8,283	7,559	6,360
Health Benefits Segment
Segment Reporting Information [Line Items]
Premiums	34,934	33,376	106,701	98,626	131,964	115,725	102,643
Product revenue	0	0	0	0	0	0	0
Service fees	1,810	1,689	5,323	4,862	6,520	6,003	5,628
Total operating revenue	36,744	35,065	112,024	103,488	138,484	121,728	108,271
Operating gain (loss)	1,847	1,634	6,154	5,266	6,061	5,884	5,125
Carelon Total
Segment Reporting Information [Line Items]
Premiums	422	412	1,261	1,105	1,499	1,786	1,466
Product revenue	5,177	3,972	14,058	10,841	14,978	12,657	10,384
Service fees	200	224	608	670	882	842	643
Total operating revenue	11,892	10,403	35,135	30,088	40,803	35,079	27,631
Operating gain (loss)	650	641	2,003	1,831	2,323	1,802	1,389
Carelon Services Segment
Segment Reporting Information [Line Items]
Premiums	422	412	1,261	1,105	1,499	1,786	1,466
Product revenue	0	0	0	0	0	0	0
Service fees	196	224	604	670	882	842	643
Total operating revenue	3,374	3,154	10,127	9,085	12,277	9,648	5,720
Operating gain (loss)	173	125	518	438	455	118	28
CarelonRx Segment [Member]
Segment Reporting Information [Line Items]
Premiums	0	0	0	0	0	0	0
Product revenue	5,177	3,972	14,058	10,841	14,978	12,657	10,384
Service fees	4	0	4	0	0	0	0
Total operating revenue	8,518	7,249	25,008	21,003	28,526	25,431	21,911
Operating gain (loss)	477	516	1,485	1,393	1,868	1,684	1,361
Corporate & Other Segment
Segment Reporting Information [Line Items]
Premiums	0	0	0	0	0	0	0
Product revenue	0	0	0	0	0	0	0
Service fees	34	18	50	37	51	68	44
Total operating revenue	242	211	780	799	1,017	602	337
Operating gain (loss)	(741)	(24)	(942)	(73)	(101)	(127)	(154)
Segment Eliminations [Member]
Segment Reporting Information [Line Items]
Premiums	(97)	(66)	(246)	(148)	(234)	(138)	0
Total operating revenue	(6,398)	(6,054)	(20,184)	(18,382)	(24,644)	(20,466)	(15,431)
Operating gain (loss)	0	0	0	0	0	0	0
Unaffiliated
Segment Reporting Information [Line Items]
Total operating revenue	42,480	39,625	127,755	115,993	155,660	136,943	120,808
Unaffiliated | Health Benefits Segment
Segment Reporting Information [Line Items]
Total operating revenue	36,744	35,065	112,024	103,488	138,484	121,728	108,271
Unaffiliated | Carelon Total
Segment Reporting Information [Line Items]
Total operating revenue	5,799	4,608	15,927	12,616	17,359	15,285	12,493
Unaffiliated | Carelon Services Segment
Segment Reporting Information [Line Items]
Total operating revenue	618	636	1,865	1,775	2,381	2,628	2,109
Unaffiliated | CarelonRx Segment [Member]
Segment Reporting Information [Line Items]
Total operating revenue	5,181	3,972	14,062	10,841	14,978	12,657	10,384
Unaffiliated | Corporate & Other Segment
Segment Reporting Information [Line Items]
Total operating revenue	34	18	50	37	51	68	44
Unaffiliated | Segment Eliminations [Member]
Segment Reporting Information [Line Items]
Total operating revenue	(97)	(66)	(246)	(148)	(234)	(138)	0
Affiliated [Member] | Carelon Total
Segment Reporting Information [Line Items]
Total operating revenue	6,093	5,795	19,208	17,472	23,444	19,794	15,138
Affiliated [Member] | Carelon Services Segment
Segment Reporting Information [Line Items]
Total operating revenue	2,756	2,518	8,262	7,310	9,896	7,020	3,611
Affiliated [Member] | CarelonRx Segment [Member]
Segment Reporting Information [Line Items]
Total operating revenue	3,337	3,277	10,946	10,162	13,548	12,774	11,527
Affiliated [Member] | Corporate & Other Segment
Segment Reporting Information [Line Items]
Total operating revenue	208	193	730	762	966	534	293
Affiliated [Member] | Segment Eliminations [Member]
Segment Reporting Information [Line Items]
Total operating revenue	$ (6,301)	$ (5,988)	$ (19,938)	$ (18,234)	$ (24,410)	$ (20,328)	$ (15,431)