Summary of Significant Accounting Policies [Abstract] Summary of Significant Accounting Policies [Abstract] Significant Accounting Policies [Table] Significant Accounting Policies [Table] Type of Contract [Axis] Type of Contract [Axis] Type of Contract [Axis] Type of Contract [Domain] Type of Contract [Domain] Type of Contract [Domain] T-3 Contract [Member] T-3 Contract [Member] T-3 Contract [Member] MFLC Contract [Member] MFLC Contract [Member] MFLC Contract [Member] Statement, Business Segments [Axis] Business Segments [Axis] Segment [Domain] Segment [Domain] Government Contracts [Member] Government contracts. Significant Accounting Policies [Line Items] Significant Accounting Policies [Line Items] Significant Accounting Policies [Line Items] Number of administrative services, option periods Number of Administrative Services Option Periods Number of Administrative Services Option Periods Deferred transition-in costs Deferred Costs Effective date of contract Effective Date Of Contract Effective Date Of Contract Deferred revenue Deferred Revenue Costs paid and reimbursable Costs Paid And Reimbursable Costs Paid And Reimbursable Investments [Abstract] Losses from other-than-temporary impairments Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities Proceeds from sales of investments available-for-sale Proceeds from Sale of Available-for-sale Securities Gross realized gains Available-for-sale Securities, Gross Realized Gains Gross realized losses Available-for-sale Securities, Gross Realized Losses Income Taxes [Abstract] Income Taxes [Abstract] Income Taxes Income Tax Disclosure [Text Block] Schedule of Investments [Table] Schedule of Investments [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Current [Member] Investment-Available-for-Sale Securities, Current [Member] Investment-Available-for-Sale Securities, Current [Member] Noncurrent [Member] Investment-Available-for-Sale Securities, Noncurrent [Member] Investment-Available-for-Sale Securities, Noncurrent [Member] Schedule of Available-for-sale Securities, Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] Asset-Backed Securities [Member] Asset-backed Securities [Member] U.S. Government and Agencies [Member] US Government Agencies Debt Securities [Member] Obligations of States and Other Political Subdivisions [Member] US States and Political Subdivisions Debt Securities [Member] Corporate Debt Securities [Member] Corporate Debt Securities [Member] Schedule of Available-for-sale Securities [Line Items] Schedule of Available-for-sale Securities [Line Items] Less than 12 Months, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Less than 12 Months, Unrealized Losses Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses 12 Months or More, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value 12 Months or More, Unrealized Losses Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses Total, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Total, Unrealized Losses Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses Statement of Financial Position [Abstract] Statement [Table] Statement [Table] Current [Member] Statement [Line Items] Statement [Line Items] Investments available for sale, amortized cost Available-for-sale Securities, Amortized Cost Basis Premiums receivable, allowance for doubtful accounts Allowance for Doubtful Accounts Receivable, Current Preferred stock, par value Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized Preferred Stock, Shares Authorized Preferred stock, shares issued Preferred Stock, Shares Issued Preferred stock, shares outstanding Preferred Stock, Shares Outstanding Common stock, par value Common Stock, Par or Stated Value Per Share Common stock, shares authorized Common Stock, Shares Authorized Common stock, shares issued Common Stock, Shares, Issued Treasury stock, shares Treasury Stock, Shares Fair Value Measurements [Abstract] FAIR VALUE MEASUREMENTS [Abstract] Assets Measured at Fair Value on Recurring Basis Fair Value, Assets Measured on Recurring Basis [Table Text Block] Changes in the Balances of Level 3 Financial Assets on Recurring Basis Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Financial Assets Measured at Fair Value on a Non-Recurring Basis Fair Value Measurements, Nonrecurring [Table Text Block] Changes in the Balances of Level 3 Financial Assets, Measured on a Non-Recurring Basis Fair Value Assets Measured On Non-Recurring Basis Unobservable Input Reconciliation [Table Text Block] Fair Value Assets Measured On Non-Recurring Basis Unobservable Input Reconciliation [Table Text Block] Quantitative Information About Level 3 Fair Value Measurements Fair Value Inputs, Assets, Quantitative Information [Table Text Block] Basis of Presentation [Abstract] BASIS OF PRESENTATION [Abstract] Basis of Presentation Basis of Accounting [Text Block] Effective income tax rate (as a percentage) Effective Income Tax Rate, Continuing Operations Tax expense, net against gain on sale of discontinued operations Discontinued Operation, Tax Effect of Income (Loss) from Disposal of Discontinued Operation Gain (loss) on sale of discontinued operation, before tax Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax Valuation allowance release against deferred tax assets Valuation Allowance, Deferred Tax Asset, Change in Amount Tax effect of discontinued operation Discontinued Operation, Tax Effect of Discontinued Operation Income (loss) from discontinued operation, before income tax Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax Income Tax Contingency [Table] Income Tax Contingency [Table] Litigation Case Type [Axis] Litigation Case Type [Axis] Litigation Case Type [Axis] Litigation Case Type [Domain] Litigation Case Type [Domain] AmCareco Litigation [Member] AmCareco Litigation [Member] AmCareco Litigation [Member] Income Tax Contingency [Line Items] Income Tax Contingency [Line Items] Deferred tax assets Deferred Tax Assets, Gross, Noncurrent Valuation allowance, deferred tax asset Deferred Tax Assets, Valuation Allowance, Noncurrent Federal statutory income tax rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate Fair Value Inputs, Assets, Quantitative Information [Table] Fair Value Inputs, Assets, Quantitative Information [Table] Western Region Operations [Member] Western Region Operations [Member] Western Region Operations [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value, Inputs, Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Valuation Technique [Axis] Valuation Technique [Axis] Valuation Technique [Domain] Valuation Technique [Domain] Monte Carlo Simulation Approach [Member] Monte Carlo Simulation Approach [Member] Monte Carlo Simulation Approach [Member] Income Approach [Member] Income Approach Valuation Technique [Member] Unobservable Input [Axis] Unobservable Input [Axis] Unobservable Input [Axis] Unobservable Input [Domain] Unobservable Input [Domain] Unobservable Input [Domain] Health Net Health Care Expenditures [Member] Health Net Health Care Expenditures [Member] Health Net Health Care Expenditures [Member] National Health Care Expenditures [Member] National Health Care Expenditures [Member] National Health Care Expenditures [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Weighted Average [Member] Weighted Average [Member] Fair Value Inputs, Assets, Quantitative Information [Line Items] Fair Value Inputs, Assets, Quantitative Information [Line Items] Embedded contractual derivative Embedded Derivative, Fair Value of Embedded Derivative Asset Goodwill Goodwill Deferred revenue related to transition-related services provided in connection with Medicare PDP business sale Health Care Expenditures, range (as a percentage) Fair Value Input Health Care Expenditures Range Fair Value Input, Health Care Expenditures Range (as a percentage) Discount Rate, range (as a percentage) Fair Value Inputs, Discount Rate Costs estimated in connection with providing transition related services Costs estimated in connection with providing transition related services Costs estimated in connection with providing transition related services Document and Entity Information [Abstract] Document and Entity Information [Abstract] Entities [Table] Entities [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Entity Information [Line Items] Entity Information [Line Items] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Treasury Stock, Shares Stock Repurchase Program [Abstract] Stock Repurchase Program Abstract Stock Repurchase Program Treasury Stock [Text Block] Schedule of Goodwill [Table] Schedule of Goodwill [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Provider Networks [Member] Provider Networks [Member] Provider Networks [Member] Customer Relationships and Other [Member] Customer Relationships [Member] Goodwill [Line Items] Goodwill [Line Items] Ratio of fair value to carrying value Ratio of fair value to carrying value Ratio of fair value to carrying value Goodwill, beginning of the period Goodwill allocated to Medicare PDP business sold Goodwill, Written off Related to Sale of Business Unit Goodwill, end of the period Finite-Lived Intangible Assets Intangible Assets, Net (Excluding Goodwill) [Abstract] Gross Carrying Amount Finite-Lived Intangible Assets, Gross Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Net Balance Finite-Lived Intangible Assets, Net Weighted Average Life (in years) Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Future Amortization Expense, Current to Five Succeeding Fiscal Years Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract] 2012 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 2013 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2014 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2015 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2016 Finite-Lived Intangible Assets, Amortization Expense, Year Five Income Statement [Abstract] Statement, Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Revenues Revenues [Abstract] Health plan services premiums Health Care Organization, Premium Revenue Government contracts Contracts Revenue Net investment income Investment Income, Net Administrative service fees and other income Health Care Organization, Other Revenue Divested operations and services revenue Divested operations and services revenue Divested operations and services revenue Total revenues Revenues Expenses Operating Expenses [Abstract] Health plan services (excluding depreciation and amortization) Health Care Organization, Expenses, Net Government contracts Contract Revenue Cost General and administrative General and Administrative Expense Selling Selling Expense Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Interest Interest Expense Divested operations and services expenses Divested operations and services expenses Divested operations and services expenses Adjustment to loss on sale of Northeast health plan subsidiaries Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal Total expenses Operating Expenses Income (loss) from continuing operations before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest Income tax provision (benefit) Income Tax Expense (Benefit) Income (loss) from continuing operations Income (Loss) from Continuing Operations Attributable to Parent Discontinued operations: Discontinued Operation, Income (Loss) from Discontinued Operation Disclosures [Abstract] Income (loss) from discontinued operation, net of tax Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, Net of Tax Gain on sale of discontinued operation, net of tax Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax Income (loss) from discontinued operation, net of tax Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Net income (loss) Net Income (Loss) Attributable to Parent Net income (loss) per share - basic: Earnings Per Share, Basic [Abstract] Income (loss) from continuing operations Income (Loss) from Continuing Operations, Per Basic Share Income (loss) from discontinued operation, net of tax Income (Loss) from Discontinued Operations, Net of Tax, Per Basic Share Net income (loss) per share - basic Earnings Per Share, Basic Net income (loss) per share - diluted: Earnings Per Share, Diluted [Abstract] Income (loss) from continuing operations Income (Loss) from Continuing Operations, Per Diluted Share Income (loss) from discontinued operation, net of tax Income (Loss) from Discontinued Operations, Net of Tax, Per Diluted Share Net income (loss) per share - diluted Earnings Per Share, Diluted Weighted average shares outstanding: Weighted Average Shares Outstanding Abstract Weighted average shares outstanding [Abstract] Basic Weighted Average Number of Shares Outstanding, Basic Diluted Weighted Average Number of Shares Outstanding, Diluted Financing Arrangements [Abstract] Financing Arrangements [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] 6.375% Senior Notes [Member] Six Point Three Seven Five Percent Senior Notes [Member] 6.375% Senior Notes [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Debt instrument, aggregate principal amount Debt Instrument, Face Amount Debt instrument, stated interest rate (as a percentage) Debt Instrument, Interest Rate, Stated Percentage Debt instrument, maturity date Debt Instrument, Maturity Date Contingent payment of principal (as a percentage) Long Term Debt Contingent Payment of Principal Percent of Principal Description of percentage of principal due if payment of principal is triggered due to certain events. Default on senior notes Debt Instrument, Debt Default, Amount Call feature (as a percentage) Debt Instrument Call Feature Percent Of Principal Description of the call price as a percentage of outstanding principal. Number of days in year per debt terms Number of Days in Year Per Debt Terms Number of Days in Year Per Debt Terms Number of months in year per debt terms Number of Months in Year Per Debt Terms Number of Months in Year Per Debt Terms Number of days in month, per debt terms Number of Days in Month, Per Debt Terms Number of Days in Month, Per Debt Terms Debt instrument, benchmark for variable rate basis Debt Instrument, Description of Variable Rate Basis Treasury rate basis points (as a percentage) Debt Instrument, Basis Spread on Variable Rate Senior note, failure to perform covenant Debt Instrument Failure To Perform Covenant Debt Instrument Failure to Perform Covenant Senior note, grace period for defaulted payment Debt Instrument Grace Period For Defaulted Payment Debt Instrument Grace Period for Defaulted Payment Threshold for noncompliance Threshold Amount For Noncompliance With Senior Note Indenture Threshold Amount For Noncompliance With Senior Note Indenture. Accelerated principal amount threshold Minimum Borrowed Aggregate Principal Amount Minimum Borrowed Aggregate Principal Amount Senior notes amount Senior Notes, Noncurrent Sale of Businesses [Abstract] Sale of Businesses [Abstract] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Table] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Table] Divested Operations and Services [Member] Divested Operations and Services [Member] Divested Operations and Services [Member] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Groups, Including Discontinued Operations, Name [Domain] Disposal Groups, Including Discontinued Operations, Name [Domain] PDP Sale Proceeds [Member] PDP Sale Proceeds [Member] PDP Sale Proceeds [Member] Additional PDP Sale Proceeds [Member] Additional PDP Sale Proceeds [Member] Additional PDP Sale Proceeds [Member] PDP Sale [Member] PDP Sale [Member] PDP Sale [Member] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Disposal date Disposal Date Proceeds from divestiture of business Proceeds from Divestiture of Businesses Sales price component Sales price component Sales price component Number of customers Number of Customers The number of individuals the entity provides health benefits to. Deferred revenue, recognition period Deferred Revenue, Recognition Period Deferred Revenue, Recognition Period Discount rate Divestiture, sale threshold Disposal Group, Sale, Calculated Threshold For a sale of a disposal group, the calculated losses used as a threshold per the contract. Discontinued operations revenues Disposal Group, Including Discontinued Operation, Revenue Income (loss) from operations before income taxes Disposal Group, Including Discontinued Operation, Operating Income (Loss) Subsequent Events [Abstract] Line of Credit [Member] Short-term Debt, Type [Axis] Short-term Debt, Type [Axis] Short-term Debt, Type [Domain] Short-term Debt, Type [Domain] Standby Letters of Credit [Member] Standby Letters of Credit [Member] Letter of Credit [Member] Letter of Credit [Member] Bridge Loan [Member] Bridge Loan [Member] Base Rate [Axis] Base Rate [Axis] The base rate options the Company can choose to pay. Base Rate [Domain] Base Rate [Domain] Base Rate [Domain]. Federal Funds [Member] Federal Funds [Member] Federal Funds [Member]. Eurodollar Rate Plus 45 to 105 Basis Points [Member] Eurodollar Rate Plus 45 to 105 Basis Points [Member] Eurodollar Rate Plus 45 to 105 Basis Points [Member]. Eurodollar Rate Plus 145 to 205 Basis Points [Member] Eurodollar Rate Plus 145 to 205 Basis Points [Member] Eurodollar Rate Plus 145 to 205 Basis Points [Member] Debt Instrument Variable Rate Basis By Name [Axis] Debt Instrument Variable Rate Basis By Name [Axis] Debt Instrument Variable Rate Basis By Name [Axis] Debt Instrument Variable Base Rate By Name [Domain] Debt Instrument Variable Base Rate By Name [Domain] Debt Instrument Variable Base Rate [Domain] Variable Base Rate A [Member] Variable Base Rate A [Member] Variable Base Rate A [Member] Variable Base Rate B [Member] Variable Base Rate B [Member] Variable Base Rate B [Member] Maximum amount available for borrowing under the revolving credit facility Line of Credit Facility, Maximum Borrowing Capacity Line of credit facility, maturity date Line of Credit Facility, Expiration Date Revolving credit facility, borrowing capacity Line of Credit Facility, Current Borrowing Capacity Additional borrowing capacity Line of Credit Facility, Increase, Additional Borrowing Capacity Additional amount that may be borrowed under the credit facility. Revolving credit facility outstanding balance Line of Credit Facility, Amount Outstanding Revolving credit facility, remaining capacity Line of Credit Facility, Remaining Borrowing Capacity Debt instrument basis description Line of Credit Facility, Interest Rate Description Debt instrument, basis spread (as a percentage) Debt Instrument Basis Margin Debt Instrument Basis Margin Debt instrument, basis spread on variable rate (as a percentage) Interest period on credit facility (in months) Interest Period for Credit Facility, in Months Interest Period for Credit Facility, in Months Line of credit default limit Line of Credit Default Limit Threshold Amount for Noncompliance with line of credit agreement. Limit of uninsured judgment not stayed within 60 days Limit Of Uninsured Judgment Not Stayed Within 60 Days Limit of uninsured judgment not stayed within 60 days. Limit of uninsured judgment not stayed, period (in days) Limit Of Uninsured Judgment Not Stayed Period Limit Of Uninsured Judgment Not Stayed Period Outstanding letters of credit Letters of Credit Outstanding, Amount Amounts drawn on letters of credit Draw On Outstanding Letters Of Credit Amount Draw On Outstanding Letters Of Credit Amount Less than 12 months, number of securities Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Number Of Positions Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Number Of Positions 12 months or more, number of securities Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Number Of Positions Available for Sale Securities, Continuous Unrealized Loss Position, 12 Months Or Longer, Number of Positions. Total, number of securities Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Significant Accounting Policies Significant Accounting Policies [Text Block] Significant Accounting Policies [Table] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Government Contracts Concentration Risk [Member] Concentration Risk [Line Items] Concentration Risk [Line Items] Concentration risk, percentage Concentration Risk, Percentage Restricted cash and cash equivalents Restricted Cash and Cash Equivalents, Noncurrent Investment securities held by trustees or agencies Assets Held-in-trust Accumulated Other Comprehensive (Loss) Income Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Carrying Amount of Goodwill Schedule of Goodwill [Table Text Block] Schedule of Intangible Assets Schedule of Acquired Finite-Lived Intangible Assets by Major Class [Table Text Block] Estimated Annual Pretax Amortization Expense For Other Intangible Assets Schedule of Expected Amortization Expense [Table Text Block] Segment Reporting Information, Additional Information [Abstract] Segment Information Segment Reporting Disclosure [Text Block] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Current [Member] Current Assets [Member] Current Assets [Member] Noncurrent [Member] Noncurrent Assets [Member] Noncurrent Assets [Member] Fair Value by Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Measurements, Nonrecurring [Member] Residential Mortgage-Backed Securities [Member] Residential Mortgage Backed Securities [Member] Commercial Mortgage-Backed Securities [Member] Commercial Mortgage Backed Securities [Member] Other Asset-Backed Securities [Member] Other Asset Backed Securities [Member] Other Asset Backed Securities [Member] U.S. Government and Agencies [Member] US Treasury and Government [Member] U.S. Treasury Securities [Member] US Treasury Securities [Member] U.S. Agency Securities [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Investments at fair value Available-for-sale Securities, Fair Value Disclosure Embedded Derivative, Fair Value of Embedded Derivative Asset Total assets at fair value Assets, Fair Value Disclosure Goodwill allocated to Medicare PDP business sold Disposal Group, Including Discontinued Operation, Goodwill Transfers of Liabilities, Levels 1 to Level 2 Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount Transfers of Assets, Levels 1 to Level 2 Fair Value, Assets, Level 1 to Level 2 Transfers, Amount Transfers of Liabilities, Levels 2 to Level 1 Fair Value, Liabilities, Level 2 to Level 1 Transfers, Amount Transfers of Assets, Levels 2 to Level 1 Fair Value, Assets, Level 2 to Level 1 Transfers, Amount Fair Value of Investments Available-for-Sale Schedule of Available-for-sale Securities Reconciliation [Table Text Block] Available-for-Sale Current Investments Classified by Contractual Maturity Date Investments Classified by Contractual Maturity Date [Table Text Block] Schedule of Unrealized Loss on Investments Schedule of Unrealized Loss on Investments [Table Text Block] Number of Securities Included in Loss Position of Current Investments Number Of Securities Included In Loss Position Of Current And Noncurrent Investments [Table Text Block] Number Of Securities Included In Loss Position Of Current And Noncurrent Investments [Table Text Block] Subsequent Event [Table] Subsequent Event [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Financing [Axis] Financing [Axis] Financing [Domain] Financing [Domain] Dividends [Axis] Dividends [Axis] Dividends [Domain] Dividends [Domain] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Sale [Axis] Sale [Axis] Sale [Domain] Sale [Domain] Extraordinary Item [Axis] Extraordinary Item [Axis] Extraordinary Item [Domain] Extraordinary Item [Domain] Bankruptcy of Party [Axis] Bankruptcy of Party [Axis] Bankruptcy [Domain] Bankruptcy [Domain] Loss on Receivables [Axis] Loss on Receivables [Axis] Loss on Receivables [Domain] Loss on Receivables [Domain] Product Recall [Axis] Product Recall [Axis] Product Recall [Domain] Product Recall [Domain] Litigation Status [Axis] Litigation Status [Axis] Litigation Status [Domain] Litigation Status [Domain] Litigation Case [Axis] Litigation Case [Axis] New Contract [Axis] New Contract [Axis] New Contract [Domain] New Contract [Domain] Cancellation of Contract [Axis] Cancellation of Contract [Axis] Cancellation of Contract [Domain] Cancellation of Contract [Domain] Impairment in Value of Asset [Axis] Impairment in Value of Asset [Axis] Impairment in Value of Asset [Domain] Impairment in Value of Asset [Domain] Expropriation of Assets [Axis] Expropriation of Assets [Axis] Expropriation of Assets [Domain] Expropriation of Assets [Domain] Change in Tax Status [Axis] Change in Tax Status [Axis] Change in Tax Status [Domain] Change in Tax Status [Domain] Subsequent Event [Line Items] Subsequent Event [Line Items] Maximum account deficit payment Maximum account deficit payment Maximum deficit payment from Account Stock Repurchase Program [Table] Stock Repurchase Program [Table] Stock Repurchase Program [Axis] Stock Repurchase Program [Axis] Stock Repurchase Program [Axis] Stock Repurchase Program [Domain] Stock Repurchase Program [Domain] Stock Repurchase Program [Domain] 2010 Stock Repurchase Program [Member] Stock Repurchase Program Two Thousand Ten [Member] Stock repurchase program two thousand ten [Member] 2011 Stock Repurchase Program [Member] Stock Repurchase Program Two Thousand Eleven [Member] Stock repurchase program two thousand eleven [Member] Equity, Class of Treasury Stock [Line Items] Stock repurchase program authorized amount Stock Repurchase Program, Authorized Amount Treasury stock shares acquired Treasury Stock, Shares, Acquired Treasury stock value acquired cost method Treasury Stock, Value, Acquired, Cost Method Average price of repurchased stock per share Treasury Stock Acquired, Average Cost Per Share Stock repurchase program remaining authorized repurchase amount Stock Repurchase Program, Remaining Authorized Repurchase Amount Statement of Cash Flows [Abstract] CASH FLOWS FROM OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income (loss) Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Amortization and depreciation Depreciation, Depletion and Amortization Adjustment to loss on sale of business Gain on sale of discontinued operation Share-based compensation expense Share-based Compensation Deferred income taxes Deferred Income Tax Expense (Benefit) Excess tax benefit on share-based compensation Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Operating Activities Net realized (gain) loss on investments Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments Other changes Other Noncash Income (Expense) Changes in assets and liabilities, net of effects of acquisitions and dispositions: Increase (Decrease) in Operating Capital [Abstract] Premiums receivable and unearned premiums Premiums receivable and unearned premiums The change in the premiums receivable balance and the change in the unearned portion of premiums written, excluding the portion amortized into income. Other current assets, receivables and noncurrent assets Increase (Decrease) in Other Operating Assets Amounts receivable/payable under government contracts Amounts receivable payable under government contracts The change in contracts receivable and other current liabilities. Reserves for claims and other settlements Increase (Decrease) in Health Care Insurance Liabilities Accounts payable and other liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Net cash provided by (used in) operating activities Net Cash Provided by (Used in) Operating Activities CASH FLOWS FROM INVESTING ACTIVITIES: Net Cash Provided by (Used in) Investing Activities [Abstract] Sales of investments Maturities of investments Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities Purchases of investments Payments to Acquire Available-for-sale Securities Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Net cash received from sale of business Proceeds from Divestiture of Businesses, Net of Cash Divested Purchase price adjustment on sale of Northeast Health Plans Sales (purchases) of restricted investments and other Payments for (Proceeds from) Other Investing Activities Net cash provided by investing activities Net Cash Provided by (Used in) Investing Activities CASH FLOWS FROM FINANCING ACTIVITIES: Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from exercise of stock options and employee stock purchases Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options Excess tax benefit on share-based compensation Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities Repurchases of common stock Payments for Repurchase of Common Stock Borrowings under financing arrangements Proceeds from Lines of Credit Repayment of borrowings under financing arrangements Repayments of Lines of Credit Net increase in checks outstanding, net of deposits Increase (Decrease) in Outstanding Checks, Financing Activities Customer funds administered Increase (Decrease) in Other Deposits Net cash (used in) provided by financing activities Net Cash Provided by (Used in) Financing Activities Net increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents, beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents, end of period SUPPLEMENTAL CASH FLOWS DISCLOSURE: Supplemental Cash Flow Information [Abstract] Interest paid Interest Paid Income taxes paid Income Taxes Paid, Net Health Care Organization Revenue and Expense [Table] Health Care Organization Revenue and Expense [Table] Health Care Organization Revenue and Expense [Table] Incurred claims related to 2011 and prior [Member] Incurred Claims Prior Years [Member] Incurred Claims Prior Years [Member] Incurred claims related to first quarter of 2012 [Member] Incurred Claims Prior Quarter [Member] Incurred Claims Prior Quarter [Member] Incurred claims, Prior Period gross [Member] Incurred Claims Prior Period Gross [Member] Incurred Claims Prior Period Gross [Member] Change to provision for adverse deviation [Member] Change to provision For Adverse Deviation [Member] Prior Period Development Reduction [Member] Incurred claims, Prior Period net [Member] Prior Period Development Net [Member] Prior Period Development Net [Member] Health Care Organization Revenue and Expense [Line Items] Health Care Organization Revenue and Expense [Line Items] Health Care Organization Revenue and Expense [Line Items] Health plan services Due in one year or less, Amortized Cost Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis Due after one year through five years, Amortized Cost Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis Due after five years through ten years, Amortized Cost Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis Due after ten years, Amortized Cost Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis Available for sale securities, Amortized Cost Due in one year or less, Estimated Fair Value Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value Due after one year through five years, Estimated Fair Value Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value Due after five years through ten years, Estimated Fair Value Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value Due after ten years, Estimated Fair Value Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value Available for sale securities, Estimated Fair Value Available-for-sale Securities, Current Fair Value Measurements Fair Value Disclosures [Text Block] Investments Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Financing Arrangements Debt Disclosure [Text Block] Amortized Cost Gross Unrealized Holding Gains Available-for-sale Securities, Gross Unrealized Gains Gross Unrealized Holding Losses Available-for-sale Securities, Gross Unrealized Losses Carrying Value, Current Carrying Value, Noncurrent Available-for-sale Securities, Noncurrent Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value by Asset Class [Axis] Asset Class [Axis] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, by Asset Class [Domain] Fair Value by Asset Class [Domain] Available-For-Sale Investments [Member] Debt Securities [Member] Embedded Contractual Derivative [Member] Derivative Financial Instruments, Assets [Member] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Opening balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Transfers into Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 Transfers out of Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 Total gains or losses for the period Total Gains And Losses [Abstract] Total Gains And Losses [Abstract] Realized in net income Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Unrealized in accumulated other comprehensive income Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Purchases, issues, sales and settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, Sales, Issues, Settlements [Abstract] Purchases/additions Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Issues Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issues Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Closing balance Change in unrealized gains (losses) included in net income for assets held at the end of the reporting period Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Unrealized Gains Losses Still Held Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Unrealized Gains (Losses) Still Held. Changes in Level 3 Financial Assets and Liabilities, Non-Recurring Basis Changes in Level 3 Financial Assets and Liabilities, Non-Recurring Basis [Abstract] Changes in Level 3 Financial Assets and Liabilities, Non-Recurring Basis [Abstract] Beginning balance: goodwill of discontinued operation Ending balance: goodwill of discontinued operation Beginning balance, Deferred revenue related to transition-related services provided in connection with Medicare PDP business sale Deferred revenue, realized in net income Deferred Revenue, Revenue Recognized Deferred revenue, Additions Deferred Revenue, Additions Ending balance, Deferred revenue related to transition-related services provided in connection with Medicare PDP business sale Segment Information Schedule of Segment Reporting Information, by Segment [Table Text Block] Premium Revenue By Line Of Business Premium Revenue By Line Of Business [Table Text Block] Tabular disclosure of health plan services premium revenue by line of business. Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies [Table] Commitments and Contingencies [Table] Commitments and Contingencies [Table] Loss Contingencies by Nature of Contingency [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Litigation Related to Lost Personal Information [Member] Litigation Related to Lost Personal Information [Member] Litigation Related to Lost Personal Information [Member] Commitments and Contingencies [Line Items] Commitments and Contingencies [Line Items] Commitments and Contingencies [Line Items] Litigation and Investigations Related to Unaccounted-for Server Drives [Abstract] Litigation and Investigations Related to Unaccounted-for Server Drives [Abstract] Litigation and Investigations Related to Unaccounted-for Server Drives [Abstract] Number of pending litigations Number of Pending Litigations Number of Pending Litigations Total number of people with information on drives Total Number Of People With Information On Drives The total number of people whose personal information were on the server drives. Period of free credit monitoring services Period of Free Credit Monitoring Services Period of Free Credit Monitoring Services Remaining actions currently pending, after consolidation Number of Pending Litigations After Consolidation Number of Pending Litigations After Consolidation Estimated putative class members Estimated Number Of Putative Class The estimated number of putative class members Damages sought for each class member Damages Sought For Each Member Class Statutory damages sought for each member in class Number of named plaintiffs' claims on which arbitration was requested Number of Named Plaintiffs' Claims on Which Arbitration was Requested Number of named plaintiffs' claims on which arbitration was requested. Number of motions for arbitration granted Number of Motions for Arbitration Granted Number of motions for arbitration granted. Number of litigation matters Number Of Litigation Matters Number Of Litigation Matters Number of separate state receivers Number Of Separate State Receivers Number Of Separate State Receivers Number of health plans liquidated Number Of Health Plans Liquidated Number Of Health Plans Liquidated Former subsidiary merged Former Subsidiary Merged Former Subsidiary Merged Payments for legal settlements Litigation Charge Amount AmCareco Litigation Charge Amount Medi-Cal provider reimbursement rate reduction (as a percentage) Percent Reduction In Provider Reimbursement Rates Percent Reduction In Provider Reimbursement Rates Cash and Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Investments Investment, Policy [Policy Text Block] Fair Value of Financial Instruments Fair Value of Financial Instruments, Policy [Policy Text Block] Health Plan Services Health Care Cost Health Care Entities, Policy [Policy Text Block] Concentrations of Credit Risk Concentration Risk Disclosure [Text Block] Comprehensive Income Comprehensive Income, Policy [Policy Text Block] Earnings Per Share Earnings Per Share, Policy [Policy Text Block] Goodwill and Other Intangible Assets Goodwill and Intangible Assets, Policy [Policy Text Block] Restricted Assets Restricted Assets [Policy Text Block] The entity's accounting policy with respect to restricted cash and investments. Government Contracts Government Contractors, Policy [Policy Text Block] ASSETS Assets [Abstract] Cash and cash equivalents Investments-available-for-sale (amortized cost: 2012-$XX, 2011-$1,528,091) Premiums receivable, net of allowance for doubtful accounts (2012-$XX, 2011-$3,318) Premiums Receivable, at Carrying Value Amounts receivable under government contracts Contract Receivable Other receivables Other Receivables Deferred taxes Deferred Tax Assets, Net of Valuation Allowance, Current Other assets Other Assets, Current Total current assets Assets, Current Property and equipment, net Property, Plant and Equipment, Net Other intangible assets, net Intangible Assets, Net (Excluding Goodwill) Deferred taxes Deferred Tax Assets, Net of Valuation Allowance, Noncurrent Investments-available-for-sale-noncurrent (amortized cost: 2012-$0, 2011-$2,450) Other noncurrent assets Other Assets, Noncurrent Total Assets Assets LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities and Equity [Abstract] Reserves for claims and other settlements Liability for Claims and Claims Adjustment Expense, Disability, Accident and Health Health care and other costs payable under government contracts Other Liabilities, Current Unearned premiums Unearned Premiums Accounts payable and other liabilities Accounts Payable, Other, Current Total current liabilities Liabilities, Current Senior notes payable Borrowings under revolving credit facility Long-term Line of Credit, Noncurrent Other noncurrent liabilities Other Liabilities, Noncurrent Total Liabilities Liabilities Commitments and contingencies Commitments and Contingencies Stockholders' Equity: Stockholders' Equity Attributable to Parent [Abstract] Preferred stock ($0.001 par value, 10,000 shares authorized, none issued and outstanding) Preferred Stock, Value, Issued Common stock ($0.001 par value, 350,000 shares authorized; issued 2012-XX shares; 2011-146,804 shares) Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Treasury common stock, at cost (2012-XX shares of common stock; 2011-64,847 shares of common stock) Treasury Stock, Value Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Total Stockholders' Equity Stockholders' Equity Attributable to Parent Total Liabilities and Stockholders' Equity Liabilities and Equity Sale of Medicare PDP Business and Northeast Business Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Commercial Premium Revenue [Member] Commercial Premium Revenue [Member] Commercial Premium Revenue [Member] Medicare Premium Revenue [Member] Medicare Premium Revenue [Member] Medicare Premium Revenue [Member] Medicaid Premium Revenue [Member] Medicaid Premium Revenue [Member] Medicaid Premium Revenue [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Health plans services premiums Statement of Other Comprehensive Income [Abstract] Statement of Other Comprehensive Income [Abstract] Other comprehensive income before tax: Other Comprehensive Income (Loss), before Tax [Abstract] Unrealized gains (losses) on investments available-for-sale: Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, [Abstract] Unrealized holding gains arising during the period Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax Less: Reclassification adjustments for gains included in earnings Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, before Tax Unrealized gains on investments available-for-sale, net Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax Defined benefit pension plans: Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax, [Abstract] Prior service cost arising during the period Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Arising During Period, before Tax Net loss arising during the period Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax Less: Amortization of prior service cost and net loss inluded in net periodic pension cost Other Comprehensive Income Amortization Of Defined Benefit Plan Net Prior Service Cost And Net Loss Recognized In Net Periodic Benefit Cost Before Tax Amortization of defined benefit plan net prior service cost and net loss recognized in net periodic benefit cost before tax. Defined benefit pension plans, net Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax Other comprehensive income, before tax Other Comprehensive Income (Loss), before Tax Income tax expense (benefit) related to components of other comprehensive income Other Comprehensive Income (Loss), Tax Other comprehensive (loss) income, net of tax Other Comprehensive Income (Loss), Net of Tax Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Statement of Stockholders' Equity [Abstract] Statement, Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock [Member] Common Stock [Member] Additional Paid-In Capital [Member] Additional Paid-in Capital [Member] Common Stock Held In Treasury [Member] Treasury Stock [Member] Retained Earnings [Member] Retained Earnings [Member] Accumulated Other Comprehensive Income (Loss) [Member] Accumulated Other Comprehensive Income (Loss) [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Balance Balance, shares Shares, Issued Other comprehensive income (loss) Exercise of stock options and vesting of restricted stock units Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Exercise of stock options and vesting of restricted stock units, shares Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Share-based compensation expense Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Tax benefit related to equity compensation plans Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net Repurchases of common stock Repurchases of common stock, shares Balance, shares Balance Accounting Policies [Abstract] Checks outstanding Checks Outstanding Checks outstanding, net of Deposits Losses recognized from other-than-temporary impairments Other than Temporary Impairment Losses, Investments, Available-for-sale Securities Fair value of fixed rate borrowings Notes Payable, Fair Value Disclosure Fair value of variable rate borrowings Lines of Credit, Fair Value Disclosure Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Beginning, Unrealized Gains (Losses) on investments available-for-sale Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Other comprehensive (loss) income, Unrealized Gains (Losses) on investments available-for-sale Other Comprehensive Income (Loss), Available-for-sale Securities, Net of Tax Other comprehensive income (loss) arising during the period from gross appreciation (loss) in value of the total unsold available-for-sale securities and reclassification adjustments for gains realized in earnings during the period Ending, Unrealized Gains (Losses) on investments available-for-sale Beginning, Defined Benefit Pension Plans Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax Other comprehensive (loss) income, Defined Benefit Pension Plans Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax Ending, Defined Benefit Pension Plans Beginning, Accumulated Other Comprehensive Income (Loss) Other comprehensive (loss) income, Accumulated Other Comprehensive Income (Loss) Ending, Accumulated Other Comprehensive Income (Loss) Government Contracts [Member] Corporate/Other/Eliminations [Member] Intersegment Elimination [Member] Number of reportable segments (in segments) Number of Reportable Segments Revenues from external sources Revenue from External Customers Intersegment revenues Segment Reporting Information, Intersegment Revenue Segment pretax income (loss) Subsequent Events [Text Block] Subsequent Events [Text Block] 2010 Stock Repurchase Program [Member] 2010 Stock Repurchase Program [Member] Stock repurchase program two thousand ten [Member] Common stock equivalents (in shares) Weighted Average Number Diluted Shares Outstanding Adjustment Anti-dilutive securities excluded from computation of diluted earnings per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount