Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Revenues	$ 321,629	$ 290,912	$ 267,908
Net investment income (loss)	838	1,199	798
Total revenues	322,467	292,111	268,706
Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	205,121	184,618	171,289
Front Store
Disaggregation of Revenue [Line Items]
Revenues	22,780	21,315	19,655
Premiums
Disaggregation of Revenue [Line Items]
Revenues	85,330	76,132	69,364
Other
Disaggregation of Revenue [Line Items]
Revenues	8,398	8,847	7,600
Operating Segments | Health Care Benefits
Disaggregation of Revenue [Line Items]
Revenues	90,844	81,515	74,926
Net investment income (loss)	476	586	483
Total revenues	91,409	82,186	75,467
Operating Segments | Health Care Benefits | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
Operating Segments | Health Care Benefits | Front Store
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
Operating Segments | Health Care Benefits | Premiums
Disaggregation of Revenue [Line Items]
Revenues	85,274	76,064	69,301
Operating Segments | Health Care Benefits | Other
Disaggregation of Revenue [Line Items]
Revenues	5,659	5,536	5,683
Operating Segments | Pharmacy Services
Disaggregation of Revenue [Line Items]
Revenues	157,787	143,194	132,663
Net investment income (loss)	0	0	0
Total revenues	169,236	153,022	141,938
Operating Segments | Pharmacy Services | Pharmacy network
Disaggregation of Revenue [Line Items]
Total revenues	97,668	91,715	85,045
Operating Segments | Pharmacy Services | Mail choice
Disaggregation of Revenue [Line Items]
Total revenues	70,466	60,547	56,071
Operating Segments | Pharmacy Services | Other
Disaggregation of Revenue [Line Items]
Total revenues	1,102	760	822
Operating Segments | Pharmacy Services | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	168,134	152,262	141,116
Operating Segments | Pharmacy Services | Front Store
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
Operating Segments | Pharmacy Services | Premiums
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
Operating Segments | Pharmacy Services | Other
Disaggregation of Revenue [Line Items]
Revenues	1,102	760	822
Operating Segments | Retail/ LTC
Disaggregation of Revenue [Line Items]
Revenues	72,874	66,078	60,208
Net investment income (loss)	(44)	17	0
Total revenues	106,594	100,105	91,198
Operating Segments | Retail/ LTC | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	82,010	76,121	70,176
Operating Segments | Retail/ LTC | Front Store
Disaggregation of Revenue [Line Items]
Revenues	22,780	21,315	19,655
Operating Segments | Retail/ LTC | Premiums
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
Operating Segments | Retail/ LTC | Other
Disaggregation of Revenue [Line Items]
Revenues	1,848	2,652	1,367
Corporate/ Other
Disaggregation of Revenue [Line Items]
Revenues	124	125	111
Net investment income (loss)	406	596	315
Total revenues	530	721	426
Corporate/ Other | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
Corporate/ Other | Front Store
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
Corporate/ Other | Premiums
Disaggregation of Revenue [Line Items]
Revenues	56	68	63
Corporate/ Other | Other
Disaggregation of Revenue [Line Items]
Revenues	68	57	48
Intersegment Eliminations
Disaggregation of Revenue [Line Items]
Net investment income (loss)	0	0	0
Total revenues	(45,302)	(43,923)	(40,323)
Intersegment Eliminations | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	(45,023)	(43,765)	(40,003)
Intersegment Eliminations | Front Store
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
Intersegment Eliminations | Premiums
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
Intersegment Eliminations | Other
Disaggregation of Revenue [Line Items]
Revenues	$ (279)	$ (158)	$ (320)