Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Aggregate carrying amount of life insurance contracts and equity investments, fair value	$ 740	$ 1,006

Life Insurance Contracts And Equity Investments, Fair Value

No definition available.

Name:	cnc_LifeInsuranceContractsAndEquityInvestmentsFairValue
Namespace Prefix:	cnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant