Segment Reporting - Retrospective Adjustments to Segment Composition (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting, Other Significant Reconciling Item [Line Items]
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, Other Significant Reconciling Item [Line Items]
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, Other Significant Reconciling Item [Line Items]
Total revenues	46,891	43,254	137,697	125,807
Adjusted operating income (loss)	1,878	1,695	5,452	4,996
Operating Segments | Pharmacy & Consumer Wellness
Segment Reporting, Other Significant Reconciling Item [Line Items]
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, Other Significant Reconciling Item [Line Items]
Total revenues	105	142	376	378
Adjusted operating income (loss)	(347)	(388)	(982)	(1,147)
Intersegment Eliminations
Segment Reporting, Other Significant Reconciling Item [Line Items]
Total revenues	(12,400)	(11,970)	(38,608)	(35,776)
Adjusted operating income (loss)	$ 0	0	$ 0	0
As Reported
Segment Reporting, Other Significant Reconciling Item [Line Items]
Total revenues		81,159		238,621
Adjusted operating income (loss)		4,233		13,526
As Reported | Operating Segments | Health Care Benefits
Segment Reporting, Other Significant Reconciling Item [Line Items]
Total revenues		22,511		68,376
Adjusted operating income (loss)		1,544		5,126
As Reported | Operating Segments | Health Services
Segment Reporting, Other Significant Reconciling Item [Line Items]
Total revenues		43,216		125,489
Adjusted operating income (loss)		1,877		5,368
As Reported | Operating Segments | Pharmacy & Consumer Wellness
Segment Reporting, Other Significant Reconciling Item [Line Items]
Total revenues		26,706		78,410
Adjusted operating income (loss)		1,398		4,865
As Reported | Corporate/ Other | Corporate/ Other
Segment Reporting, Other Significant Reconciling Item [Line Items]
Total revenues		142		378
Adjusted operating income (loss)		(417)		(1,277)
As Reported | Intersegment Eliminations
Segment Reporting, Other Significant Reconciling Item [Line Items]
Total revenues		(11,416)		(34,032)
Adjusted operating income (loss)		(169)		(556)
Adjustments
Segment Reporting, Other Significant Reconciling Item [Line Items]
Total revenues		0		0
Adjusted operating income (loss)		116		432
Adjustments | Operating Segments | Health Care Benefits
Segment Reporting, Other Significant Reconciling Item [Line Items]
Total revenues		(15)		(45)
Adjusted operating income (loss)		97		299
Adjustments | Operating Segments | Health Services
Segment Reporting, Other Significant Reconciling Item [Line Items]
Total revenues		38		318
Adjusted operating income (loss)		(182)		(372)
Adjustments | Operating Segments | Pharmacy & Consumer Wellness
Segment Reporting, Other Significant Reconciling Item [Line Items]
Total revenues		531		1,471
Adjusted operating income (loss)		3		(181)
Adjustments | Corporate/ Other | Corporate/ Other
Segment Reporting, Other Significant Reconciling Item [Line Items]
Total revenues		0		0
Adjusted operating income (loss)		29		130
Adjustments | Intersegment Eliminations
Segment Reporting, Other Significant Reconciling Item [Line Items]
Total revenues		(554)		(1,744)
Adjusted operating income (loss)		$ 169		$ 556