Capital contribution by related party.

No definition available.

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

- Definition

Percentage of credit claimed for each of remaining four years.

+ References

No definition available.

+ Details

Name:	moh_PercentageOfCreditClaimedForEachOfRemainingFourYears
Namespace Prefix:	moh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of credit claimed for first three years.

+ References

No definition available.

+ Details

Name:	moh_PercentageOfCreditClaimedForFirstThreeYears
Namespace Prefix:	moh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Principal amount of loan by party.

+ References

No definition available.

+ Details

Name:	moh_PrincipalAmountOfLoanByParty
Namespace Prefix:	moh_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Tax credit claimed as percentage of original investment amount.

+ References

No definition available.

+ Details

Name:	moh_TaxCreditClaimedAsPercentageOfOriginalInvestmentAmount
Namespace Prefix:	moh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Tax Credit Claimed, Term

+ References

No definition available.

+ Details

Name:	moh_TaxCreditClaimedTerm
Namespace Prefix:	moh_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of revenue from providing administrative services, including, but not limited to, accounting, tax, legal, regulatory filing, and share registration activities of managed funds and investment accounts of independent third parties and related and affiliated entities.

+ References

No definition available.

+ Details

Name:	us-gaap_AdministrativeServicesRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of cash inflow from debt classified as other.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3255-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

+ Details

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

- Definition

The carrying amount of the consolidated Variable Interest Entity's assets included in the reporting entity's statement of financial position.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (bb)
-URI http://asc.fasb.org/extlink&oid=64801991&loc=d3e5710-111685

+ Details

Name:	us-gaap_VariableInterestEntityConsolidatedCarryingAmountAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The carrying amount of the consolidated Variable Interest Entity's liabilities included in the reporting entity's statement of financial position.

+ References

+ Details

Name:	us-gaap_VariableInterestEntityConsolidatedCarryingAmountLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of financial or other support the reporting entity has provided (explicitly or implicitly) to the Variable Interest Entity (VIE) that it was not previously contractually required to provide or that the reporting entity intends to provide, including, for example, situations in which the reporting entity assisted the VIE in obtaining another type of support.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=64801991&loc=SL6759159-111685

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_VariableInterestEntityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=moh_NewMexicoDataCenterMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis=us-gaap_VariableInterestEntityPrimaryBeneficiaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Variable Interest Entities (VIEs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2011
Variable Interest Entity [Line Items]
Administrative fee revenue	$ 55	$ 69	$ 11
New Mexico Data Center
Variable Interest Entity [Line Items]
Tax credit claimed as a percentage of original investment amount				39.00%
Tax credit claimed, term				7 years
Percentage of credit claimed for first three years				5.00%
Percentage of credit claimed for remaining four years				6.00%
Capital contribution by related party				$ 6
Principal amount of loan by party				16
Proceeds from other debt	6	6		$ 21
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Amount paid for health care services	122	117	$ 32
Variable interest entity, total assets	18	17
Variable interest entity, total liabilities	$ 18	$ 17