Segment Reporting - Reconciliation of Financial Measures of Segments to Consolidated Totals (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Revenues from external customers	$ 89,487	$ 80,958	$ 263,078	$ 238,106
Net investment income (loss)	277	201	885	515
Total revenues	89,764	81,159	263,963	238,621
Adjusted operating income (loss)	4,456	4,349	13,307	13,958
Operating Segments | Health Care Benefits
Segment Reporting Information [Line Items]
Revenues from external customers	26,089	22,375	78,302	67,993
Net investment income (loss)	187	101	556	278
Total revenues	26,296	22,496	78,920	68,331
Adjusted operating income (loss)	1,536	1,641	4,901	5,425
Operating Segments | Health Services
Segment Reporting Information [Line Items]
Revenues from external customers	44,064	40,544	127,907	116,801
Net investment income (loss)	0	0	0	0
Total revenues	46,891	43,254	137,697	125,807
Adjusted operating income (loss)	1,878	1,695	5,452	4,996
Co-payments	3,200	2,900	10,700	9,800
Operating Segments | Pharmacy & Consumer Wellness
Segment Reporting Information [Line Items]
Revenues from external customers	19,321	18,007	56,826	53,215
Net investment income (loss)	(2)	(10)	(4)	(44)
Total revenues	28,872	27,237	85,578	79,881
Adjusted operating income (loss)	1,389	1,401	3,936	4,684
Corporate/ Other | Corporate/ Other
Segment Reporting Information [Line Items]
Revenues from external customers	13	32	43	97
Net investment income (loss)	92	110	333	281
Total revenues	105	142	376	378
Adjusted operating income (loss)	(347)	(388)	(982)	(1,147)
Intersegment Eliminations
Segment Reporting Information [Line Items]
Intersegment revenues	(12,400)	(11,970)	(38,608)	(35,776)
Net investment income (loss)	0	0	0	0
Total revenues	(12,400)	(11,970)	(38,608)	(35,776)
Adjusted operating income (loss)	0	0	0	0
Intersegment Eliminations | Health Care Benefits
Segment Reporting Information [Line Items]
Intersegment revenues	20	20	62	60
Intersegment Eliminations | Health Services
Segment Reporting Information [Line Items]
Intersegment revenues	2,827	2,710	9,790	9,006
Intersegment Eliminations | Pharmacy & Consumer Wellness
Segment Reporting Information [Line Items]
Intersegment revenues	$ 9,553	$ 9,240	$ 28,756	$ 26,710