Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Revenues	$ 88,647	$ 80,490	$ 173,591	$ 157,148
Net investment income (loss)	274	146	608	314
Total revenues	88,921	80,636	174,199	157,462
Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	55,062	51,326	107,847	98,816
Front Store
Disaggregation of Revenue [Line Items]
Revenues	5,629	5,736	11,226	11,049
Premiums
Disaggregation of Revenue [Line Items]
Revenues	25,108	21,260	49,460	42,891
Other
Disaggregation of Revenue [Line Items]
Revenues	2,848	2,168	5,058	4,392
Operating Segments | Health Care Benefits
Disaggregation of Revenue [Line Items]
Revenues	26,521	22,633	52,213	45,618
Net investment income (loss)	205	88	369	177
Total revenues	26,747	22,741	52,624	45,835
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	25,095	21,245	49,434	42,859
Operating Segments | Health Care Benefits | Other
Disaggregation of Revenue [Line Items]
Revenues	1,447	1,408	2,821	2,799
Operating Segments | Health Services
Disaggregation of Revenue [Line Items]
Revenues	43,032	39,946	83,843	76,257
Net investment income (loss)	0	0	0	0
Total revenues	46,215	42,938	90,806	82,553
Operating Segments | Health Services | Pharmacy network
Disaggregation of Revenue [Line Items]
Total revenues	27,477	25,896	55,069	50,024
Operating Segments | Health Services | Mail & specialty
Disaggregation of Revenue [Line Items]
Total revenues	17,229	16,283	33,374	30,951
Operating Segments | Health Services | Other
Disaggregation of Revenue [Line Items]
Total revenues	1,509	759	2,363	1,578
Operating Segments | Health Services | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	44,706	42,179	88,443	80,975
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	1,509	759	2,363	1,578
Operating Segments | Pharmacy & Consumer Wellness
Disaggregation of Revenue [Line Items]
Revenues	19,079	17,877	37,505	35,208
Net investment income (loss)	1	(18)	(2)	(34)
Total revenues	28,784	26,746	56,706	52,644
Operating Segments | Pharmacy & Consumer Wellness | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	22,614	20,442	44,394	40,412
Operating Segments | Pharmacy & Consumer Wellness | Front Store
Disaggregation of Revenue [Line Items]
Revenues	5,629	5,736	11,226	11,049
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	540	586	1,088	1,217
Corporate/ Other
Disaggregation of Revenue [Line Items]
Revenues	15	34	30	65
Net investment income (loss)	68	76	241	171
Total revenues	83	110	271	236
Corporate/ Other | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Corporate/ Other | Front Store
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Corporate/ Other | Premiums
Disaggregation of Revenue [Line Items]
Revenues	13	15	26	32
Corporate/ Other | Other
Disaggregation of Revenue [Line Items]
Revenues	2	19	4	33
Intersegment Eliminations
Disaggregation of Revenue [Line Items]
Net investment income (loss)	0	0	0	0
Total revenues	(12,908)	(11,899)	(26,208)	(23,806)
Intersegment Eliminations | Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	(12,258)	(11,295)	(24,990)	(22,571)
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	$ (650)	$ (604)	$ (1,218)	$ (1,235)