Commitments And Contingencies (Details) $ in Millions	9 Months Ended
	Sep. 30, 2015 USD ($) class_actions
Commitments And Contingencies [Line Items]
Gross premium tax rate, state of California	2.35%
Possible losses, in excess of established reserves, minimum	$ 0.0
Possible losses, in excess of established reserves, maximum	250.0
International Business Machines Corporation [Member]
Commitments And Contingencies [Line Items]
Long-term purchase commitment, amount	407.4
Affiliated Computer Services, Inc. [Member]
Commitments And Contingencies [Line Items]
Long-term purchase commitment, amount	$ 31.4
In re WellPoint, Inc. Out-of-Network UCR Rates Litigation [Member]
Commitments And Contingencies [Line Items]
Number of putative class actions consolidated into a single lawsuit | class_actions	11