Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Revenues	$ 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
Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	56,198	52,375	164,045	151,191
Front Store
Disaggregation of Revenue [Line Items]
Revenues	5,371	5,581	16,597	16,630
Premiums
Disaggregation of Revenue [Line Items]
Revenues	24,657	21,003	74,117	63,894
Other
Disaggregation of Revenue [Line Items]
Revenues	3,261	1,999	8,319	6,391
Operating Segments | Health Care Benefits
Disaggregation of Revenue [Line Items]
Revenues	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
Operating Segments | Health Care Benefits | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Health Care Benefits | Front Store
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Health Care Benefits | Premiums
Disaggregation of Revenue [Line Items]
Revenues	24,645	20,989	74,079	63,848
Operating Segments | Health Care Benefits | Other
Disaggregation of Revenue [Line Items]
Revenues	1,464	1,406	4,285	4,205
Operating Segments | Health Services
Disaggregation of Revenue [Line Items]
Revenues	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
Operating Segments | Health Services | Pharmacy network
Disaggregation of Revenue [Line Items]
Total revenues	27,981	26,334	83,050	76,358
Operating Segments | Health Services | Mail & specialty
Disaggregation of Revenue [Line Items]
Total revenues	17,004	16,318	50,378	47,269
Operating Segments | Health Services | Other
Disaggregation of Revenue [Line Items]
Total revenues	1,906	602	4,269	2,180
Operating Segments | Health Services | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	44,985	42,652	133,428	123,627
Operating Segments | Health Services | Front Store
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Health Services | Premiums
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Health Services | Other
Disaggregation of Revenue [Line Items]
Revenues	1,906	602	4,269	2,180
Operating Segments | Pharmacy & Consumer Wellness
Disaggregation of Revenue [Line Items]
Revenues	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
Operating Segments | Pharmacy & Consumer Wellness | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	22,977	21,084	67,371	61,496
Operating Segments | Pharmacy & Consumer Wellness | Front Store
Disaggregation of Revenue [Line Items]
Revenues	5,371	5,581	16,597	16,630
Operating Segments | Pharmacy & Consumer Wellness | Premiums
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Pharmacy & Consumer Wellness | Other
Disaggregation of Revenue [Line Items]
Revenues	526	582	1,614	1,799
Corporate/ Other | Corporate/ Other
Disaggregation of Revenue [Line Items]
Revenues	13	32	43	97
Net investment income (loss)	92	110	333	281
Total revenues	105	142	376	378
Corporate/ Other | Corporate/ Other | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Corporate/ Other | Corporate/ Other | Front Store
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Corporate/ Other | Corporate/ Other | Premiums
Disaggregation of Revenue [Line Items]
Revenues	12	14	38	46
Corporate/ Other | Corporate/ Other | Other
Disaggregation of Revenue [Line Items]
Revenues	1	18	5	51
Intersegment Eliminations
Disaggregation of Revenue [Line Items]
Net investment income (loss)	0	0	0	0
Total revenues	(12,400)	(11,970)	(38,608)	(35,776)
Intersegment Eliminations | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	(11,764)	(11,361)	(36,754)	(33,932)
Intersegment Eliminations | Front Store
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Intersegment Eliminations | Premiums
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Intersegment Eliminations | Other
Disaggregation of Revenue [Line Items]
Revenues	$ (636)	$ (609)	$ (1,854)	$ (1,844)