Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Disaggregation of Revenue [Line Items]
Revenues	$ 102,239	$ 94,878	$ 294,735	$ 273,701
Net investment income (loss)	632	550	1,639	1,398
Total revenues	102,871	95,428	296,374	275,099
Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	59,548	54,659	167,404	154,036
Front Store
Disaggregation of Revenue [Line Items]
Revenues	5,192	5,196	15,803	15,847
Premiums
Disaggregation of Revenue [Line Items]
Revenues	33,719	30,925	100,734	91,983
Other
Disaggregation of Revenue [Line Items]
Revenues	3,780	4,098	10,794	11,835
Health Care Benefits
Disaggregation of Revenue [Line Items]
Revenues	35,431	32,555	105,667	96,577
Net investment income (loss)	513	423	1,307	1,076
Health Services
Disaggregation of Revenue [Line Items]
Revenues	42,354	40,794	120,568	115,954
Net investment income (loss)	(1)	(1)	10	(3)
Pharmacy & Consumer Wellness
Disaggregation of Revenue [Line Items]
Revenues	24,441	21,515	68,460	61,127
Net investment income (loss)	0	0	0	0
Corporate/ Other
Disaggregation of Revenue [Line Items]
Revenues	13	14	40	43
Net investment income (loss)	120	128	322	325
Operating Segments \| Health Care Benefits
Disaggregation of Revenue [Line Items]
Net investment income (loss)	513	423	1,307	1,076
Total revenues	35,993	32,996	107,061	97,707
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	33,739	30,914	100,731	91,947
Operating Segments \| Health Care Benefits \| Other
Disaggregation of Revenue [Line Items]
Revenues	1,741	1,659	5,023	4,684
Operating Segments \| Health Services
Disaggregation of Revenue [Line Items]
Net investment income (loss)	(1)	(1)	10	(3)
Total revenues	49,266	44,129	139,181	126,585
Operating Segments \| Health Services \| Pharmacy network
Disaggregation of Revenue [Line Items]
Total revenues	26,408	24,136	74,187	66,448
Operating Segments \| Health Services \| Mail & specialty
Disaggregation of Revenue [Line Items]
Total revenues	20,392	17,214	58,071	52,127
Operating Segments \| Health Services \| Other
Disaggregation of Revenue [Line Items]
Total revenues	2,467	2,780	6,913	8,013
Operating Segments \| Health Services \| Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	46,800	41,350	132,258	118,575
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	2,467	2,780	6,913	8,013
Operating Segments \| Pharmacy & Consumer Wellness
Disaggregation of Revenue [Line Items]
Net investment income (loss)	0	0	0	0
Total revenues	36,214	32,423	101,707	90,986
Operating Segments \| Pharmacy & Consumer Wellness \| Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	30,428	26,666	84,135	73,463
Operating Segments \| Pharmacy & Consumer Wellness \| Front Store
Disaggregation of Revenue [Line Items]
Revenues	5,192	5,196	15,803	15,847
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	594	561	1,769	1,676
Corporate/ Other \| Corporate/ Other
Disaggregation of Revenue [Line Items]
Net investment income (loss)	120	128	322	325
Total revenues	133	142	362	368
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	11	34	36
Corporate/ Other \| Corporate/ Other \| Other
Disaggregation of Revenue [Line Items]
Revenues	2	3	6	7
Intersegment Eliminations
Disaggregation of Revenue [Line Items]
Net investment income (loss)	0	0	0	0
Total revenues	(18,735)	(14,262)	(51,937)	(40,547)
Intersegment Eliminations \| Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	(17,680)	(13,357)	(48,989)	(38,002)
Intersegment Eliminations \| Front Store
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Intersegment Eliminations \| Premiums
Disaggregation of Revenue [Line Items]
Revenues	(31)	0	(31)	0
Intersegment Eliminations \| Other
Disaggregation of Revenue [Line Items]
Revenues	(1,024)	(905)	(2,917)	(2,545)
Intersegment Eliminations \| Health Care Benefits
Disaggregation of Revenue [Line Items]
Total revenues	(49)	(18)	(87)	(54)
Intersegment Eliminations \| Health Services
Disaggregation of Revenue [Line Items]
Total revenues	(6,913)	(3,336)	(18,603)	(10,634)
Intersegment Eliminations \| Pharmacy & Consumer Wellness
Disaggregation of Revenue [Line Items]
Total revenues	$ (11,773)	$ (10,908)	$ (33,247)	$ (29,859)