Significant Accounting Policies (Medicaid/Medi-Cal Adjustments) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2011
Health Care Organization Revenue and Expense [Line Items]
Medicaid retro rate adjustment	$ 0		$ 42,000,000
Percent reduction in provider reimbursement rates					10.00%
Health plan services premiums	2,578,874,000	2,618,927,000	5,210,943,000	5,239,876,000
Reinstated Medicaid premium tax [Member]
Health Care Organization Revenue and Expense [Line Items]
Taxes, Other	35,700,000		35,700,000
Medicaid Premium Revenue [Member]
Health Care Organization Revenue and Expense [Line Items]
Health plan services premiums	591,700,000	491,000,000	1,191,900,000	943,700,000
Medicaid Premium Revenue [Member] | Reinstated Medicaid premium revenue[Member]
Health Care Organization Revenue and Expense [Line Items]
Health plan services premiums	35,700,000		35,700,000
Reinstated retroactive Medicaid premium taxes [Member] | Reinstated Medicaid premium tax [Member]
Health Care Organization Revenue and Expense [Line Items]
Taxes, Other	$ 25,400,000