Segment Reporting - Reconciliation of Financial Measures of Segments to Consolidated Totals (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Revenues from external customers	$ 90,840	$ 88,647	$ 178,823	$ 173,591
Net investment income (loss)	394	274	848	608
Total revenues	91,234	88,921	179,671	174,199
Adjusted operating income (loss)	3,744	4,481	6,701	8,851
Operating Segments | Health Care Benefits
Segment Reporting Information [Line Items]
Revenues from external customers	32,157	26,521	64,022	52,213
Net investment income (loss)	300	205	653	369
Total revenues	32,475	26,747	64,711	52,624
Adjusted operating income (loss)	938	1,541	1,670	3,365
Operating Segments | Health Services
Segment Reporting Information [Line Items]
Revenues from external customers	38,694	43,032	75,160	83,843
Net investment income (loss)	(2)	0	(2)	0
Total revenues	42,171	46,215	82,456	90,806
Adjusted operating income (loss)	1,915	1,894	3,278	3,574
Co-payments	2,800	3,400	6,200	7,500
Operating Segments | Pharmacy & Consumer Wellness
Segment Reporting Information [Line Items]
Revenues from external customers	19,974	19,079	39,612	37,505
Net investment income (loss)	0	1	0	(2)
Total revenues	29,838	28,784	58,563	56,706
Adjusted operating income (loss)	1,243	1,413	2,420	2,547
Corporate/ Other | Corporate/ Other
Segment Reporting Information [Line Items]
Revenues from external customers	15	15	29	30
Net investment income (loss)	96	68	197	241
Total revenues	111	83	226	271
Adjusted operating income (loss)	(352)	(367)	(667)	(635)
Intersegment Eliminations
Segment Reporting Information [Line Items]
Intersegment revenues	(13,361)	(12,908)	(26,285)	(26,208)
Net investment income (loss)	0	0	0	0
Total revenues	(13,361)	(12,908)	(26,285)	(26,208)
Adjusted operating income (loss)	0	0	0	0
Intersegment Eliminations | Health Care Benefits
Segment Reporting Information [Line Items]
Intersegment revenues	18	21	36	42
Intersegment Eliminations | Health Services
Segment Reporting Information [Line Items]
Intersegment revenues	3,479	3,183	7,298	6,963
Intersegment Eliminations | Pharmacy & Consumer Wellness
Segment Reporting Information [Line Items]
Intersegment revenues	$ 9,864	$ 9,704	$ 18,951	$ 19,203