Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Disaggregation of Revenue [Line Items]
Revenues	$ 98,428	$ 90,840	$ 192,496	$ 178,823
Net investment income (loss)	487	394	1,007	848
Total revenues	98,915	91,234	193,503	179,671
Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	55,349	50,980	107,856	99,377
Front Store
Disaggregation of Revenue [Line Items]
Revenues	5,368	5,281	10,611	10,651
Premiums
Disaggregation of Revenue [Line Items]
Revenues	34,195	30,667	67,015	61,058
Other
Disaggregation of Revenue [Line Items]
Revenues	3,516	3,912	7,014	7,737
Health Care Benefits
Disaggregation of Revenue [Line Items]
Revenues	35,831	32,157	70,236	64,022
Net investment income (loss)	407	300	794	653
Health Services
Disaggregation of Revenue [Line Items]
Revenues	40,118	38,694	78,214	75,160
Net investment income (loss)	(3)	(2)	11	(2)
Pharmacy & Consumer Wellness
Disaggregation of Revenue [Line Items]
Revenues	22,466	19,974	44,019	39,612
Net investment income (loss)	0	0	0	0
Corporate/ Other
Disaggregation of Revenue [Line Items]
Revenues	13	15	27	29
Net investment income (loss)	83	96	202	197
Operating Segments \| Health Care Benefits
Disaggregation of Revenue [Line Items]
Net investment income (loss)	407	300	794	653
Total revenues	36,258	32,475	71,068	64,711
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	34,184	30,654	66,992	61,033
Operating Segments \| Health Care Benefits \| Other
Disaggregation of Revenue [Line Items]
Revenues	1,667	1,521	3,282	3,025
Operating Segments \| Health Services
Disaggregation of Revenue [Line Items]
Net investment income (loss)	(3)	(2)	11	(2)
Total revenues	46,453	42,171	89,915	82,456
Operating Segments \| Health Services \| Pharmacy network
Disaggregation of Revenue [Line Items]
Total revenues	24,665	21,848	47,779	42,312
Operating Segments \| Health Services \| Mail & specialty
Disaggregation of Revenue [Line Items]
Total revenues	19,611	17,651	37,679	34,913
Operating Segments \| Health Services \| Other
Disaggregation of Revenue [Line Items]
Total revenues	2,180	2,674	4,446	5,233
Operating Segments \| Health Services \| Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	44,276	39,499	85,458	77,225
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	2,180	2,674	4,446	5,233
Operating Segments \| Pharmacy & Consumer Wellness
Disaggregation of Revenue [Line Items]
Net investment income (loss)	0	0	0	0
Total revenues	33,581	29,838	65,493	58,563
Operating Segments \| Pharmacy & Consumer Wellness \| Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	27,631	24,013	53,707	46,797
Operating Segments \| Pharmacy & Consumer Wellness \| Front Store
Disaggregation of Revenue [Line Items]
Revenues	5,368	5,281	10,611	10,651
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	582	544	1,175	1,115
Corporate/ Other \| Corporate/ Other
Disaggregation of Revenue [Line Items]
Net investment income (loss)	83	96	202	197
Total revenues	96	111	229	226
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	11	13	23	25
Corporate/ Other \| Corporate/ Other \| Other
Disaggregation of Revenue [Line Items]
Revenues	2	2	4	4
Intersegment Eliminations
Disaggregation of Revenue [Line Items]
Net investment income (loss)	0	0	0	0
Total revenues	(17,473)	(13,361)	(33,202)	(26,285)
Intersegment Eliminations \| Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	(16,558)	(12,532)	(31,309)	(24,645)
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	(915)	(829)	(1,893)	(1,640)
Intersegment Eliminations \| Health Care Benefits
Disaggregation of Revenue [Line Items]
Total revenues	(20)	(18)	(38)	(36)
Intersegment Eliminations \| Health Services
Disaggregation of Revenue [Line Items]
Total revenues	(6,338)	(3,479)	(11,690)	(7,298)
Intersegment Eliminations \| Pharmacy & Consumer Wellness
Disaggregation of Revenue [Line Items]
Total revenues	$ (11,115)	$ (9,864)	$ (21,474)	$ (18,951)