Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Revenues	$ 94,878	$ 89,487	$ 273,701	$ 263,078
Net investment income (loss)	550	277	1,398	885
Total revenues	95,428	89,764	275,099	263,963
Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	54,659	56,198	154,036	164,045
Front Store
Disaggregation of Revenue [Line Items]
Revenues	5,196	5,371	15,847	16,597
Premiums
Disaggregation of Revenue [Line Items]
Revenues	30,925	24,657	91,983	74,117
Other
Disaggregation of Revenue [Line Items]
Revenues	4,098	3,261	11,835	8,319
Operating Segments \| Health Care Benefits
Disaggregation of Revenue [Line Items]
Revenues	32,555	26,089	96,577	78,302
Net investment income (loss)	423	187	1,076	556
Total revenues	32,996	26,296	97,707	78,920
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	30,914	24,645	91,947	74,079
Operating Segments \| Health Care Benefits \| Other
Disaggregation of Revenue [Line Items]
Revenues	1,659	1,464	4,684	4,285
Operating Segments \| Health Services
Disaggregation of Revenue [Line Items]
Revenues	40,794	44,064	115,954	127,907
Net investment income (loss)	(1)	0	(3)	0
Total revenues	44,129	46,891	126,585	137,697
Operating Segments \| Health Services \| Pharmacy network
Disaggregation of Revenue [Line Items]
Total revenues	24,136	27,981	66,448	83,050
Operating Segments \| Health Services \| Mail & specialty
Disaggregation of Revenue [Line Items]
Total revenues	17,214	17,004	52,127	50,378
Operating Segments \| Health Services \| Other
Disaggregation of Revenue [Line Items]
Total revenues	2,780	1,906	8,013	4,269
Operating Segments \| Health Services \| Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	41,350	44,985	118,575	133,428
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	2,780	1,906	8,013	4,269
Operating Segments \| Pharmacy & Consumer Wellness
Disaggregation of Revenue [Line Items]
Revenues	21,515	19,321	61,127	56,826
Net investment income (loss)	0	(2)	0	(4)
Total revenues	32,423	28,872	90,986	85,578
Operating Segments \| Pharmacy & Consumer Wellness \| Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	26,666	22,977	73,463	67,371
Operating Segments \| Pharmacy & Consumer Wellness \| Front Store
Disaggregation of Revenue [Line Items]
Revenues	5,196	5,371	15,847	16,597
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	561	526	1,676	1,614
Corporate/ Other \| Corporate/ Other
Disaggregation of Revenue [Line Items]
Revenues	14	13	43	43
Net investment income (loss)	128	92	325	333
Total revenues	142	105	368	376
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	12	36	38
Corporate/ Other \| Corporate/ Other \| Other
Disaggregation of Revenue [Line Items]
Revenues	3	1	7	5
Intersegment Eliminations
Disaggregation of Revenue [Line Items]
Net investment income (loss)	0	0	0	0
Total revenues	(14,262)	(12,400)	(40,547)	(38,608)
Intersegment Eliminations \| Pharmacy
Disaggregation of Revenue [Line Items]
Revenues	(13,357)	(11,764)	(38,002)	(36,754)
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	$ (905)	$ (636)	$ (2,545)	$ (1,854)