Commitments and Contingencies (Details) (USD $)	9 Months Ended	12 Months Ended	9 Months Ended
	Sep. 30, 2011 AmCareco Litigation [Member]	Dec. 31, 2011 AmCareco Litigation [Member]	Sep. 30, 2012 Litigation Related to Lost Personal Information [Member] employees_members_providers actions claims	Mar. 18, 2011 Litigation Related to Lost Personal Information [Member] Customers
Litigation and Investigations Related to Unaccounted-for Server Drives [Abstract]
Number of pending litigations			3
Total number of people with information on drives			2,000,000
Period of free credit monitoring services			2 years
Remaining actions currently pending, after consolidation			2
Estimated putative class members				800,000
Damages sought for each class member			$ 1,000
Number of named plaintiffs' claims on which arbitration was requested			2
Number of motions for arbitration granted			1
Number of litigation matters		2
Number of separate state receivers		3
Number of health plans liquidated		3
Former subsidiary merged		1
Payments for legal settlements	$ 181,000,000