Segment Information - Schedule of Operating Segment Information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Total revenue	$ 5,031	$ 4,546	$ 14,934	$ 13,248
Gross margin	564	457	1,364	1,331
Impairment loss	(129)	0	(201)	0
Restructuring and separation costs	(118)	0	(161)	0
Total assets	8,954		8,954		$ 7,449
Goodwill and intangible assets, net	531		531		760
Health Plans
Segment Reporting Information [Line Items]
Total revenue	4,899	4,412	14,538	12,835
Gross margin	557	443	1,343	1,285
Impairment loss	0	0	0	0
Restructuring and separation costs	(33)	0	(33)	0
Total assets	7,031		7,031		5,897
Goodwill and intangible assets, net	488		488		513
Molina Medicaid Solutions
Segment Reporting Information [Line Items]
Total revenue	47	48	140	146
Gross margin	5	6	13	17
Impairment loss	(28)	0	(28)	0
Restructuring and separation costs	(8)	0	(8)	0
Total assets	233		233		267
Goodwill and intangible assets, net	43		43		72
Other
Segment Reporting Information [Line Items]
Total revenue	85	86	256	267
Gross margin	2	8	8	29
Impairment loss	(101)	0	(173)	0
Restructuring and separation costs	(77)	$ 0	(120)	$ 0
Total assets	1,690		1,690		1,285
Goodwill and intangible assets, net	$ 0		$ 0		$ 175

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(12))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Section 45
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