Segment Information - Reconciliation of Gross Margin by Segment to Consolidated Income (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income from continuing operations before income tax expense:
Gross margin		$ 457	$ 374	$ 1,331	$ 1,114
Revenue	[1]	4,546	3,611	13,248	10,307
Less: other operating expenses		4,428	3,498	12,936	9,996
Operating income		118	113	312	311
Other expenses, net		(26)	(15)	(76)	(45)
Income before income tax expense		92	98	236	266
Other operating
Income from continuing operations before income tax expense:
Revenue	[2]	222	187	625	509
Less: other operating expenses	[3]	(561)	(448)	(1,644)	(1,312)
Health Plans
Income from continuing operations before income tax expense:
Gross margin		443	361	1,285	1,071
Revenue	[1]	4,412	3,562	12,835	10,155
Molina Medicaid Solutions
Income from continuing operations before income tax expense:
Gross margin		6	13	17	43
Revenue	[1]	48	47	146	146
Other
Income from continuing operations before income tax expense:
Gross margin		8	0	29	0
Revenue	[1]	$ 86	$ 2	$ 267	$ 6

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

[2] Other operating revenues include premium tax revenue, health insurer fee revenue, investment income and other revenue.

[3] Other operating expenses include general and administrative expenses, premium tax expenses, health insurer fee expenses and depreciation and amortization.