Segment Reporting - Reconciliation of Financial Measures of Segments to Consolidated Totals (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Revenues from external customers	$ 80,490	$ 72,327	$ 157,148	$ 141,127
Net investment income (loss)	146	289	314	586
Total revenues	80,636	72,616	157,462	141,713
Adjusted operating income (loss)	4,810	4,887	9,293	9,092
Health Care Benefits
Segment Reporting Information [Line Items]
Total revenues	22,756	20,525	45,865	41,008
Pharmacy Services
Segment Reporting Information [Line Items]
Total revenues	42,812	38,314	82,273	74,635
Retail/ LTC
Segment Reporting Information [Line Items]
Total revenues	26,286	24,728	51,704	48,002
Operating Segments | Health Care Benefits
Segment Reporting Information [Line Items]
Revenues from external customers	22,645	20,367	45,642	40,682
Net investment income (loss)	88	137	177	285
Total revenues	22,756	20,525	45,865	41,008
Adjusted operating income (loss)	1,831	1,614	3,582	3,396
Operating Segments | Pharmacy Services
Segment Reporting Information [Line Items]
Revenues from external customers	39,859	35,745	76,055	69,058
Net investment income (loss)	0	0	0	0
Total revenues	42,812	38,314	82,273	74,635
Adjusted operating income (loss)	1,855	1,755	3,491	3,262
Copayments	3,100	2,800	6,900	6,200
Operating Segments | Retail/ LTC
Segment Reporting Information [Line Items]
Revenues from external customers	17,952	16,185	35,386	31,325
Net investment income (loss)	(18)	0	(34)	46
Total revenues	26,286	24,728	51,704	48,002
Adjusted operating income (loss)	1,862	2,049	3,467	3,443
Intersegment Eliminations
Segment Reporting Information [Line Items]
Intersegment revenues	(11,328)	(11,133)	(22,616)	(22,249)
Net investment income (loss)	0	0	0	0
Total revenues	(11,328)	(11,133)	(22,616)	(22,249)
Adjusted operating income (loss)	(183)	(162)	(387)	(337)
Intersegment Eliminations | Health Care Benefits
Segment Reporting Information [Line Items]
Intersegment revenues	23	21	46	41
Intersegment Eliminations | Pharmacy Services
Segment Reporting Information [Line Items]
Intersegment revenues	2,953	2,569	6,218	5,577
Intersegment Eliminations | Retail/ LTC
Segment Reporting Information [Line Items]
Intersegment revenues	8,352	8,543	16,352	16,631
Corporate/ Other
Segment Reporting Information [Line Items]
Revenues from external customers	34	30	65	62
Net investment income (loss)	76	152	171	255
Total revenues	110	182	236	317
Adjusted operating income (loss)	$ (555)	$ (369)	$ (860)	$ (672)