Supplemental Condensed Consolidating Financial Information - Balance Sheet (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 3,934	$ 2,819	$ 2,842	$ 2,329
Investments	1,787	1,758
Restricted investments	326	0
Receivables	1,002	974
Income taxes refundable	60	39
Due from (to) affiliates	0	0
Prepaid expenses and other current assets	174	131
Derivative asset	425	267
Total current assets	7,708	5,988
Property, equipment, and capitalized software, net	397	454
Deferred contract costs	97	86
Goodwill and intangible assets, net	531	760
Restricted investments	117	110
Investment in subsidiaries, net	0	0
Deferred income taxes	62	10
Other assets	42	41
Total assets	8,954	7,449
Current liabilities:
Medical claims and benefits payable	2,478	1,929	1,871	1,685
Amounts due government agencies	1,324	1,202
Accounts payable and accrued liabilities	485	385
Deferred revenue	468	315
Current portion of long-term debt	782	472
Derivative liability	425	267
Total current liabilities	5,962	4,570
Long-term debt	1,515	1,173
Deferred income taxes	0	15
Other long-term liabilities	48	42
Total liabilities	7,525	5,800
Total stockholders’ equity	1,429	1,649
Total liabilities and stockholders' equity	8,954	7,449
Eliminations
Current assets:
Cash and cash equivalents	0	0	0	0
Investments	0	0
Restricted investments	0
Receivables	0	0
Income taxes refundable	0	0
Due from (to) affiliates	0	0
Prepaid expenses and other current assets	0	0
Derivative asset	0	0
Total current assets	0	0
Property, equipment, and capitalized software, net	0	0
Deferred contract costs	0	0
Goodwill and intangible assets, net	0	0
Restricted investments	0	0
Investment in subsidiaries, net	(2,720)	(2,855)
Deferred income taxes	(44)	0
Other assets	(16)	(16)
Total assets	(2,780)	(2,871)
Current liabilities:
Medical claims and benefits payable	0	0
Amounts due government agencies	0	0
Accounts payable and accrued liabilities	0	0
Deferred revenue	0	0
Current portion of long-term debt	0	0
Derivative liability	0	0
Total current liabilities	0	0
Long-term debt	(16)	(16)
Deferred income taxes	(44)	0
Other long-term liabilities	0	0
Total liabilities	(60)	(16)
Total stockholders’ equity	(2,720)	(2,855)
Total liabilities and stockholders' equity	(2,780)	(2,871)
Parent Guarantor \| Reportable Legal Entities
Current assets:
Cash and cash equivalents	356	86	125	360
Investments	35	178
Restricted investments	326
Receivables	2	2
Income taxes refundable	2	17
Due from (to) affiliates	203	104
Prepaid expenses and other current assets	65	58
Derivative asset	425	267
Total current assets	1,414	712
Property, equipment, and capitalized software, net	261	301
Deferred contract costs	0	0
Goodwill and intangible assets, net	55	58
Restricted investments	0	0
Investment in subsidiaries, net	2,625	2,609
Deferred income taxes	10	10
Other assets	50	48
Total assets	4,415	3,738
Current liabilities:
Medical claims and benefits payable	0	1
Amounts due government agencies	0	0
Accounts payable and accrued liabilities	227	146
Deferred revenue	0	0
Current portion of long-term debt	782	472
Derivative liability	425	267
Total current liabilities	1,434	886
Long-term debt	1,515	1,173
Deferred income taxes	12	11
Other long-term liabilities	25	19
Total liabilities	2,986	2,089
Total stockholders’ equity	1,429	1,649
Total liabilities and stockholders' equity	4,415	3,738
Other Guarantors \| Reportable Legal Entities
Current assets:
Cash and cash equivalents	58	6	11	13
Investments	0	0
Restricted investments	0
Receivables	25	34
Income taxes refundable	0	4
Due from (to) affiliates	(5)	(5)
Prepaid expenses and other current assets	20	30
Derivative asset	0	0
Total current assets	98	69
Property, equipment, and capitalized software, net	37	46
Deferred contract costs	97	86
Goodwill and intangible assets, net	43	73
Restricted investments	0	0
Investment in subsidiaries, net	95	246
Deferred income taxes	0	0
Other assets	2	3
Total assets	372	523
Current liabilities:
Medical claims and benefits payable	0	0
Amounts due government agencies	0	0
Accounts payable and accrued liabilities	40	34
Deferred revenue	52	40
Current portion of long-term debt	0	0
Derivative liability	0	0
Total current liabilities	92	74
Long-term debt	0	0
Deferred income taxes	32	39
Other long-term liabilities	1	1
Total liabilities	125	114
Total stockholders’ equity	247	409
Total liabilities and stockholders' equity	372	523
Non-Guarantors \| Reportable Legal Entities
Current assets:
Cash and cash equivalents	3,520	2,727	$ 2,706	$ 1,956
Investments	1,752	1,580
Restricted investments	0
Receivables	975	938
Income taxes refundable	58	18
Due from (to) affiliates	(198)	(99)
Prepaid expenses and other current assets	89	43
Derivative asset	0	0
Total current assets	6,196	5,207
Property, equipment, and capitalized software, net	99	107
Deferred contract costs	0	0
Goodwill and intangible assets, net	433	629
Restricted investments	117	110
Investment in subsidiaries, net	0	0
Deferred income taxes	96	0
Other assets	6	6
Total assets	6,947	6,059
Current liabilities:
Medical claims and benefits payable	2,478	1,928
Amounts due government agencies	1,324	1,202
Accounts payable and accrued liabilities	218	205
Deferred revenue	416	275
Current portion of long-term debt	0	0
Derivative liability	0	0
Total current liabilities	4,436	3,610
Long-term debt	16	16
Deferred income taxes	0	(35)
Other long-term liabilities	22	22
Total liabilities	4,474	3,613
Total stockholders’ equity	2,473	2,446
Total liabilities and stockholders' equity	$ 6,947	$ 6,059

Medical Premium Liability Due to Agency

No definition available.

Name:	moh_MedicalPremiumLiabilityDueToAgency
Namespace Prefix:	moh_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits.