Significant Accounting Policies - Narrative (Details) people in Millions, patient in Millions, $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2023 state	Jun. 30, 2023 USD ($) clinic people patient store primaryCareMedicalClinic	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) clinic people patient Segment store state primaryCareMedicalClinic	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Significant Accounting Policies [Line Items]
Number of pharmacy plan members | people		110		110
Number of patients served per year (more than) | patient		1		1
Number of reportable segments | Segment				4
Client Health Information Network Services, Fees Expensed
Significant Accounting Policies [Line Items]
Transactions with related party		$ 15	$ 16	$ 32	$ 31
Pharmaceutical Inventory Purchases, Payments Received
Significant Accounting Policies [Line Items]
Transactions with related party		10	$ 23	29	$ 44
Other Insurance Liabilities
Significant Accounting Policies [Line Items]
Liability for future policy benefits		377		377		$ 334
Other Long-Term Insurance Liabilities
Significant Accounting Policies [Line Items]
Liability for future policy benefits		$ 4,700		$ 4,700		$ 4,700
Pharmacy & Consumer Wellness
Significant Accounting Policies [Line Items]
Number of retail locations (more than) | store		9,000		9,000
Health Services
Significant Accounting Policies [Line Items]
Number of walk in medical clinics (more than) | clinic		1,100		1,100
Number of primary care medical clinics | primaryCareMedicalClinic		177		177
Health Care Benefits
Significant Accounting Policies [Line Items]
Number of people served | people		36		36
Number of states in which the Company has entered the individual public health insurance exchange | state				8
Additional number of states in which the Company entered the individual public health insurance exchange | state	4