Significant Accounting Policies (Details) - USD ($) $ in Millions		3 Months Ended				9 Months Ended		24 Months Ended
		Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Schedule of Premium Revenue by Health Plan Type [Line Items]
Amounts due government agencies		$ 1,232				$ 1,232		$ 729
Premiums receivable		1				1		3
Total revenue	[1]	4,546			$ 3,611	13,248	$ 10,307
Anticipated Medicare risk adjustment premiums payable		17				17		4
Unrecorded receivable for Marketplace risk corridor		80				80
Unrecorded receivable for Marketplace risk corridor, prior year		52				52
Unrecorded receivable for Marketplace risk corridor, current year		28				28
Pathways
Schedule of Premium Revenue by Health Plan Type [Line Items]
Tax benefit recognized based on changes in allocation of purchase price		4
Texas | Quality Incentives
Schedule of Premium Revenue by Health Plan Type [Line Items]
Deferred revenue recognized during period			$ 51
Deferred revenue for services provided				$ 7				44
Adjustment to Previously Recognized Revenue
Schedule of Premium Revenue by Health Plan Type [Line Items]
Total revenue				$ 18
Medicaid Expansion
Schedule of Premium Revenue by Health Plan Type [Line Items]
Amounts due government agencies		298				298		208
Medical Premium Liability Due to Agency
Schedule of Premium Revenue by Health Plan Type [Line Items]
Medical premiums liability based on medical cost thresholds		323				323		214
Profit sharing liability		$ 9				$ 9		$ 10

[1] Total revenue consists primarily of premium revenue for the Health Plans segment, and service revenue for the Molina Medicaid Solutions and Other segments.