Significant Accounting Policies - Narrative (Details) people in Millions, patient in Millions	3 Months Ended
	Mar. 31, 2021 USD ($) clinic people state location Segment patient	Mar. 31, 2020 USD ($)
Significant Accounting Policies [Line Items]
Number of pharmacy plan members | people	108
Number of patients served per year | patient	1
Number of reportable segments | Segment	4
Health insurer fee	$ 0	$ 271,000,000
Related party transaction, expenses from transactions with related party	9,000,000	20,000,000
Related party transaction, other revenues from transactions with related party	$ 18,000,000	$ 21,000,000
Heartland Healthcare Services
Significant Accounting Policies [Line Items]
Number of states in which entity operates | state	4
Retail/ LTC
Significant Accounting Policies [Line Items]
Number of stores | location	9,900
Number of walk in medical clinics | clinic	1,100
Health Care Benefits
Significant Accounting Policies [Line Items]
Number of people served | people	34