v2.4.1.9

Retirement Plan (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Retirement Plan [Abstract]
Defined Contribution Plan, Cost Recognized	$ 12us-gaap_DefinedContributionPlanCostRecognized	$ 9us-gaap_DefinedContributionPlanCostRecognized	$ 7us-gaap_DefinedContributionPlanCostRecognized

X

- Details

Name:	cnc_RetirementPlanAbstract
Namespace Prefix:	cnc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The amount of the cost recognized during the period for defined contribution plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 70

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942

+ Details

Name:	us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration