Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 California Department of Health Care Services California	Mar. 25, 2014 Washington Health Plan Litigation Washington	Apr. 07, 2014 Subsequent Event Washington Health Plan Litigation Washington
Other Commitments [Line Items]
Maximum alternative minimum payment upon expiration of the settlement agreement			$ 40.0
Plan rate settlement deficit, net of valuation discount			5.0
Plan rate settlement deficit, valuation discount			0.3
Alleged overpayment by HCA related to COPES members enrollment				14.4
Alleged overpayment by HCA related to drug claims					5.8
Net assets of subsidiaries subject to restrictions	592	608
Restricted cash and investments	339.8	365.2
Aggregate statutory capital and surplus	641
Required minimum statutory capital surplus	$ 410