Summary of Significant Accounting Policies (Concentration of Credit Risk) (Details) - Customers	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2011	Dec. 31, 2010
Ten Largest Employer Group Premium Receivables [Member]
Significant Accounting Policies [Line Items]
Entity-Wide Revenue, Major Customer, Number	10	10
Concentration risk, percentage	7.00%	5.00%
Medicare Receivable From CMS [Member]
Significant Accounting Policies [Line Items]
Concentration risk, percentage	9.00%	9.00%
MedicaidReceivablePrimarilyfromDHCS [Member]
Significant Accounting Policies [Line Items]
Concentration risk, percentage	80.00%	84.00%
Ten Largest Employer Group Health Plan Services Premium Revenues [Member]
Significant Accounting Policies [Line Items]
Entity-Wide Revenue, Major Customer, Number	10	10	10
Concentration risk, percentage	9.00%	11.00%	16.00%
Medicare Health Plan Premium Revenues [Member]
Significant Accounting Policies [Line Items]
Concentration risk, percentage	20.00%	23.00%	27.00%
MedicaidPremiumRevenues [Member]
Significant Accounting Policies [Line Items]
Concentration risk, percentage	41.00%	36.00%	23.00%
Los Angles County Medi-Cal Revenue to Medicaid Revenue Ratio [Member]
Significant Accounting Policies [Line Items]
Concentration risk, percentage	58.00%	55.00%
Los Angeles County Medi-Cal Revenue to Health Plan Premiums Ratio [Member]
Significant Accounting Policies [Line Items]
Concentration risk, percentage	24.00%	19.00%
Government Contracts Concentration Risk [Member]
Significant Accounting Policies [Line Items]
Concentration risk, percentage	96.00%
Los Angeles County Contract with DHCS [Member]
Significant Accounting Policies [Line Items]
Current DHCS contract period				24 months	24 months