XML 49 R38.htm IDEA: XBRL DOCUMENT
v3.19.1

Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions | Mar. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Fair Value Disclosures [Abstract] |  |
Life insurance contracts and other private equity investments, which approximates fair value | $ 539 | $ 515

X
- Definition Life insurance contracts and cost method investments fair value disclosure + References No definition available. + Details
Name: | cnc_LifeInsuranceContractsAndCostMethodInvestmentsFairValueDisclosure
Namespace Prefix: | cnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_FairValueDisclosuresAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration