Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Aggregate carrying value which approximates fair value	$ 812	$ 515

Life Insurance Contracts And Equity Investments, Fair Value

No definition available.

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