Significant Accounting Policies (Health Plan Services Revenue Recognition) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Health Care Organizations [Line Items]
Settlement account balance, beginning	$ 0
Settlement account payment, maximum	264,000,000
Health plan services premiums	10,459,098,000	9,878,687,000	9,492,460,000
Medicare and Medicaid/Medi-Cal [Member]
Health Care Organizations [Line Items]
Percentage of health plan services premiums generated under contract	45.00%	40.00%	40.00%
Medicaid Premium Revenue [Member]
Health Care Organizations [Line Items]
Health plan services premiums	1,963,100,000	1,493,300,000	1,233,300,000
Medicaid Premium Revenue [Member] | Medi-Cal Rate Settlement Agreement [Member]
Health Care Organizations [Line Items]
Health plan services premiums	$ 0