Quarterly Information (Details) (USD $)	3 Months Ended																12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues	$ 2,743,200,000		$ 2,775,000,000	[1]	$ 2,738,400,000		$ 2,797,000,000	[2]	$ 2,837,800,000	[3]	$ 2,779,600,000		$ 2,841,300,000		$ 2,830,400,000		$ 11,053,743,000	$ 11,289,092,000	$ 11,415,436,000
Health plan services costs	2,229,300,000		2,196,600,000		2,191,900,000		2,268,700,000		2,332,800,000		2,281,400,000		2,358,500,000		2,343,700,000		8,886,547,000	9,316,313,000	8,539,754,000
Government contracts costs	124,700,000		125,300,000		127,400,000		125,500,000		137,500,000		151,800,000		153,400,000		162,300,000		502,918,000	605,074,000	1,237,884,000
Income (loss) from operations before income taxes	28,000,000		108,600,000		52,000,000	[4]	81,300,000		8,400,000		29,400,000		7,400,000		(13,600,000)		269,953,000	31,650,000	161,764,000
Loss (income) on discontinued operation, net of tax	0		0		0		0		(2,200,000)		(2,500,000)		119,400,000		(18,500,000)		0	96,382,000	11,064,000
Net income (loss)	19,800,000		66,800,000	[1]	33,500,000		50,100,000	[2]	6,000,000	[3],[5]	18,000,000	[6]	124,600,000	[7]	(26,600,000)	[8]	170,126,000	122,063,000	72,120,000
Basic (loss) earnings per share from continuing operations	$ 0.25		$ 0.84		$ 0.42		$ 0.63		$ 0.10		$ 0.25		$ 0.06		$ (0.10)		$ 2.14	$ 0.31	$ 0.69
Diluted (loss) earnings per share from continuing operations	$ 0.25	[9]	$ 0.83	[9]	$ 0.42	[9]	$ 0.62	[9]	$ 0.10	[9]	$ 0.25	[9]	$ 0.06	[9]	$ (0.10)	[9]	$ 2.12	$ 0.31	$ 0.68
Basic (loss) earnings per share on discontinued operation	$ 0.00		$ 0.00		$ 0.00		$ 0.00		$ (0.03)	[9]	$ (0.03)	[9]	$ 1.44	[9]	$ (0.22)	[9]	$ 0.00	$ 1.18	$ 0.12
Diluted (loss) earnings per share on discontinued operation	$ 0.00		$ 0.00		$ 0.00		$ 0.00		$ (0.03)	[9]	$ (0.03)	[9]	$ 1.42	[9]	$ (0.22)	[9]	$ 0.00	$ 1.16	$ 0.12
Basic (loss) earnings per share	$ 0.25		$ 0.84		$ 0.42		$ 0.63		$ 0.07	[9]	$ 0.22	[9]	$ 1.50	[9]	$ (0.32)	[9]	$ 2.14	$ 1.49	$ 0.81
Diluted (loss) earnings per share	$ 0.25	[9]	$ 0.83	[9]	$ 0.42	[9]	$ 0.62	[9]	$ 0.07	[9]	$ 0.22	[9]	$ 1.48	[9]	$ (0.32)	[9]	$ 2.12	$ 1.47	$ 0.80
G&A cost reduction efforts expense					12,900,000				8,200,000		7,200,000		10,800,000		9,500,000
Insurance reimbursement related to prior litigation															6,500,000
Gain on sale of discontinued operation, net of tax									(2,200,000)		(2,400,000)		119,400,000				0	114,834,000	0
Litigation reserve true-up															700,000
Contract breakage cost									5,000,000
Litigation related expenses									7,100,000
Medicaid Retro Rate Adjustment			32,100,000				42,200,000		31,500,000								74,300,000	21,700,000
Incurred claims from prior years [Member]
Health plan services costs													$ 7,900,000		$ 25,000,000

[1] Includes $32.1 million of Medicaid premium revenue as a result of Medicaid/Medi-Cal retroactive rate adjustments for periods prior to 2013.

[2] Includes $42.2 million of Medicaid premium revenue as a result of Medicaid/Medi-Cal retroactive rate adjustments related to 2011 and 2012.

[3] Includes $31.5 million of premium revenue as a result of Medicaid/Medi-Cal retroactive rate adjustment related to the third quarter of 2012 and prior periods.

[4] Includes a $12.9 million in pretax costs related to continuing efforts to address scale issues.

[5] Includes a $2.2 million unfavorable adjustment to the gain on sale of discontinued operation, an $8.2 million expense related to our G&A cost reduction efforts, a $5.0 million expense related to the early termination of a medical management contract and $7.1 million of litigation-related expenses.

[6] Includes a $2.4 million unfavorable adjustment to the gain on sale of discontinued operation and a $7.2 million expense related to our G&A cost reduction efforts.

[7] Includes $119.4 million gain on sale of discontinued operation related to the sale of our Medicare PDP business to CVS Caremark. Also includes $7.9 million of adverse development related to prior years recorded as part of health care costs, and a $10.8 million expense related to our G&A cost reduction efforts.

[8] Includes $25.0 million of adverse development related to prior periods recorded as part of health care costs, a $9.5 million expense related to our G&A cost reduction efforts and an unfavorable $0.7 million in pretax litigation reserve adjustment. Also includes a $6.5 million insurance reimbursement related to a prior legal settlement.

[9] The sum of the quarterly amounts may not equal the year-to-date amounts due to rounding.