Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenue [Line Items]
Revenues	$ 84,944	$ 76,658
Net investment income (loss)	334	168
Total revenues	85,278	76,826
Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	52,500	47,052
Front Store
Disaggregation of Revenue [Line Items]
Revenues	5,597	5,313
Premiums
Disaggregation of Revenue [Line Items]
Revenues	24,352	21,631
Other
Disaggregation of Revenue [Line Items]
Revenues	2,495	2,662
Operating Segments | Health Care Benefits
Disaggregation of Revenue [Line Items]
Revenues	25,692	22,985
Net investment income (loss)	164	89
Total revenues	25,877	23,094
Operating Segments | Health Care Benefits | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	0	0
Operating Segments | Health Care Benefits | Front Store
Disaggregation of Revenue [Line Items]
Revenues	0	0
Operating Segments | Health Care Benefits | Premiums
Disaggregation of Revenue [Line Items]
Revenues	24,339	21,614
Operating Segments | Health Care Benefits | Other
Disaggregation of Revenue [Line Items]
Revenues	1,374	1,391
Operating Segments | Health Services
Disaggregation of Revenue [Line Items]
Revenues	40,811	36,311
Net investment income (loss)	0	0
Total revenues	44,591	39,615
Operating Segments | Health Services | Pharmacy network
Disaggregation of Revenue [Line Items]
Total revenues	27,592	24,128
Operating Segments | Health Services | Mail & specialty
Disaggregation of Revenue [Line Items]
Total revenues	16,145	14,668
Operating Segments | Health Services | Other
Disaggregation of Revenue [Line Items]
Total revenues	854	819
Operating Segments | Health Services | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	43,737	38,796
Operating Segments | Health Services | Front Store
Disaggregation of Revenue [Line Items]
Revenues	0	0
Operating Segments | Health Services | Premiums
Disaggregation of Revenue [Line Items]
Revenues	0	0
Operating Segments | Health Services | Other
Disaggregation of Revenue [Line Items]
Revenues	854	819
Operating Segments | Pharmacy & Consumer Wellness
Disaggregation of Revenue [Line Items]
Revenues	18,426	17,331
Net investment income (loss)	(3)	(16)
Total revenues	27,922	25,898
Operating Segments | Pharmacy & Consumer Wellness | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	21,495	19,532
Operating Segments | Pharmacy & Consumer Wellness | Front Store
Disaggregation of Revenue [Line Items]
Revenues	5,597	5,313
Operating Segments | Pharmacy & Consumer Wellness | Premiums
Disaggregation of Revenue [Line Items]
Revenues	0	0
Operating Segments | Pharmacy & Consumer Wellness | Other
Disaggregation of Revenue [Line Items]
Revenues	833	1,069
Corporate/ Other
Disaggregation of Revenue [Line Items]
Revenues	15	31
Net investment income (loss)	173	95
Total revenues	188	126
Corporate/ Other | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	0	0
Corporate/ Other | Front Store
Disaggregation of Revenue [Line Items]
Revenues	0	0
Corporate/ Other | Premiums
Disaggregation of Revenue [Line Items]
Revenues	13	17
Corporate/ Other | Other
Disaggregation of Revenue [Line Items]
Revenues	2	14
Intersegment Eliminations
Disaggregation of Revenue [Line Items]
Net investment income (loss)	0	0
Total revenues	(13,300)	(11,907)
Intersegment Eliminations | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	(12,732)	(11,276)
Intersegment Eliminations | Front Store
Disaggregation of Revenue [Line Items]
Revenues	0	0
Intersegment Eliminations | Premiums
Disaggregation of Revenue [Line Items]
Revenues	0	0
Intersegment Eliminations | Other
Disaggregation of Revenue [Line Items]
Revenues	$ (568)	$ (631)