Quarterly Information (Details) (USD $)	3 Months Ended																12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues	$ 3,758,400,000		$ 3,789,900,000		$ 3,421,400,000		$ 3,038,900,000		$ 2,743,200,000		$ 2,775,000,000		$ 2,738,400,000		$ 2,797,000,000		$ 14,008,586,000	$ 11,053,743,000	$ 11,289,092,000
Health plan services expenses	3,038,200,000		3,104,000,000		2,763,200,000		2,402,300,000		2,229,300,000		2,196,600,000		2,191,900,000		2,268,700,000		11,307,751,000	8,886,547,000	9,316,313,000
Government contracts costs	147,100,000		124,400,000		133,200,000		132,000,000		124,700,000		125,300,000		127,400,000		125,500,000		536,643,000	502,918,000	605,074,000
Income (loss) from operations before income taxes	16,300,000	[1],[2]	22,700,000	[3],[4]	98,800,000	[5]	62,000,000	[6]	28,000,000		108,600,000		52,000,000		81,300,000		199,792,000	269,953,000	31,650,000
Net income (loss)	4,900,000	[1],[2]	(8,900,000)	[3],[4]	120,900,000	[5],[7]	28,800,000		19,800,000		66,800,000	[8]	33,500,000	[9]	50,100,000	[10]	145,629,000	170,126,000	122,063,000
Basic (loss) earnings per share (usd per share)	$ 0.06		$ (0.11)		$ 1.51		$ 0.36		$ 0.25		$ 0.84		$ 0.42		$ 0.63		$ 1.83	$ 2.14	$ 1.49
Diluted (loss) earnings per share (usd per share)	$ 0.06	[11]	$ (0.11)	[11]	$ 1.49		$ 0.36	[11]	$ 0.25	[11]	$ 0.83	[11]	$ 0.42	[11]	$ 0.62	[11]	$ 1.80	$ 2.12	$ 1.47
Other ACA fees	25,800,000		26,600,000		22,500,000		22,500,000
Tax Benefit Due to Worthless Stock loss			72,600,000														73,700,000
Asset impairment	3,800,000		84,700,000														88,536,000	0	0
Expenses primarily related to master services agreement	68,300,000		21,100,000
Health plan services premiums																	13,361,170,000	10,377,073,000	10,459,098,000
G&A cost reduction efforts expense													12,900,000
ACA Health Insurer Fee [Member]
Amortization of deferred cost	35,400,000		31,900,000		37,800,000		36,300,000										141,400,000
Medicaid Premium Revenue [Member]
Health plan services premiums																	4,755,900,000	2,430,300,000	1,963,100,000
Medicaid Retro Rate Adjustment [Member] | Medicaid Premium Revenue [Member]
Health plan services premiums											$ 32,100,000				$ 42,200,000			$ 74,300,000	$ 21,700,000

[1] Includes $3.8 million pretax asset impairment primarily related to our assets held for sale in connection with the Cognizant Transaction and $68.3 million in pretax expenses primarily related to the Cognizant Transaction.

[2] ncludes $35.4 million amortization of deferred costs of health insurer's fee and $25.8 million in other ACA fees.

[3] Includes $31.9 million amortization of deferred costs of health insurer's fee and $26.6 million in other ACA fees.

[4] Includes $84.7 million pretax asset impairment related to our assets held for sale in connection with the Cognizant Transaction and $21.1 million in pretax expenses primarily related to the Cognizant transaction.

[5] Includes $37.8 million amortization of deferred costs of health insurer's fee and $22.5 million in other ACA fees.

[6] Includes $36.3 million amortization of deferred costs of health insurer's fee and $22.5 million in other ACA fees.

[7] Includes tax benefit of $72.6 million, net of adjustments, as a result of a loss on the stock of one of our subsidiaries.

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

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

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

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