Basis Of Presentation [Line Items]

No definition available.

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- Definition

Health Care Organization, Insurer Fee Revenue

+ References

No definition available.

+ Details

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Namespace Prefix:	moh_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Health Care Organization, Number of Members

+ References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Maximum contract term.

+ References

No definition available.

+ Details

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- Definition

Minimum contract term.

+ References

No definition available.

+ Details

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- Definition

Number of members eligible for the health care programs.

+ References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Services Contract Renewal Term

+ References

No definition available.

+ Details

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- Definition

Services Contract Term

+ References

No definition available.

+ Details

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- Definition

The amount or range of possible amounts of gain that could be realized upon the resolution of a contingency.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6397426&loc=d3e17499-108355

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of insurance premium revenue recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(e))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of states the entity operates in as of the balance sheet date.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
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Period Type:	instant

- Details

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- Details

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- Details

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- Details

Name:	us-gaap_MajorCustomersAxis=moh_MolinaHealthcareofIllinoisInc.Member
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- Details

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- Details

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Basis of Presentation (Details) member in Millions, $ in Millions	1 Months Ended		12 Months Ended
	Aug. 31, 2017	Jun. 30, 2017	Dec. 31, 2017 USD ($) member State medical_member Segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Mar. 31, 2017 USD ($)
Basis Of Presentation [Line Items]
Number of reportable segments (in segment) \| Segment			3
Premium revenue			$ 18,854	$ 16,445	$ 13,261
Health insurer fees reimbursed			$ 0	292	244
Restatement Adjustment
Basis Of Presentation [Line Items]
Premium revenue				53	20
Health insurer fees reimbursed				(53)	(20)
Medicare Acquisition terminated
Basis Of Presentation [Line Items]
Termination fee receivable under asset purchase agreement						$ 75
Health Plans
Basis Of Presentation [Line Items]
Number of States in which company operates (in state) \| State			12
Number of members eligible for the health care programs \| member			4.5
Minimum contract terms			3 years
Maximum contract terms			4 years
Premium revenue			$ 18,854	16,445	13,261
Molina Healthcare of Illinois, Inc.
Basis Of Presentation [Line Items]
Services contract term	4 years
Services contract renewal term	4 years
Mississippi Coordinated Access Network
Basis Of Presentation [Line Items]
Services contract renewal term		2 years
Florida \| Health Plans
Basis Of Presentation [Line Items]
Premium revenue			$ 2,568	1,938	1,199
Miami Dade and Monroe Counties \| Health Plans
Basis Of Presentation [Line Items]
Number of members served, approximately (in member) \| medical_member			59,000
New Mexico \| Health Plans
Basis Of Presentation [Line Items]
Premium revenue			$ 1,368	$ 1,305	$ 1,237
Medicaid \| Florida \| Health Plans
Basis Of Presentation [Line Items]
Number of members served, approximately (in member) \| medical_member			360,000
Premium revenue			$ 1,486
Medicaid \| New Mexico \| Health Plans
Basis Of Presentation [Line Items]
Number of members served, approximately (in member) \| medical_member			224,000
Premium revenue			$ 1,205