Goodwill and Intangible Assets - Balances of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Goodwill [Line Items]
Historical goodwill		$ 577
Accumulated impairment losses		(58)
Changes in the carrying amount of goodwill
Beginning balance	$ 519
Acquisitions	96
Purchase price allocation adjustments	5
Ending balance	620
Health Plans
Goodwill [Line Items]
Historical goodwill		349
Accumulated impairment losses		(58)
Changes in the carrying amount of goodwill
Beginning balance	291
Acquisitions	96
Purchase price allocation adjustments	0
Ending balance	387
Molina Medicaid Solutions
Goodwill [Line Items]
Historical goodwill		71
Accumulated impairment losses		0
Changes in the carrying amount of goodwill
Beginning balance	71
Acquisitions	0
Purchase price allocation adjustments	0
Ending balance	71
Other
Goodwill [Line Items]
Historical goodwill		157
Accumulated impairment losses		$ 0
Changes in the carrying amount of goodwill
Beginning balance	157
Acquisitions	0
Purchase price allocation adjustments	5
Ending balance	$ 162

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=64834752&loc=SL49117168-202975

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Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=73531572&loc=d3e961-128460

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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