Significant Accounting Policies (Medicaid/Medi-Cal Adjustments) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2011
Health Care Organization Revenue and Expense [Line Items]
Medicaid retro rate adjustment	$ 32,100,000		$ 74,300,000
Percent reduction in provider reimbursement rates					10.00%
Health plan services premiums	2,606,754,000	2,578,689,000	7,817,697,000	7,818,565,000
Medicaid Premium Revenue [Member]
Health Care Organization Revenue and Expense [Line Items]
Health plan services premiums	641,600,000	475,400,000	1,833,600,000	1,419,200,000
Reinstated Medicaid premium tax [Member]
Health Care Organization Revenue and Expense [Line Items]
Taxes, Other	25,600,000		68,400,000
Reinstated Medicaid premium tax [Member] | Medicaid Premium Revenue [Member]
Health Care Organization Revenue and Expense [Line Items]
Health plan services premiums	25,600,000		68,400,000
Reinstated retroactive Medicaid premium taxes [Member] | Reinstated Medicaid premium tax [Member]
Health Care Organization Revenue and Expense [Line Items]
Taxes, Other			$ 18,800,000