Commitments and Contingencies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) actions	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Sep. 30, 2015 Plaintiff	Aug. 31, 2015 actions
Commitments and Contingencies [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 28.0
Operating Leases, Future Minimum Commitments [Abstract]
2016	57.5
2017	48.9
2018	36.3
2019	30.6
2020	29.4
Thereafter	36.9
Total minimum commitments	239.6
Unrecorded Unconditional Purchase Obligation [Abstract]
2016	286.3
2017	166.0
2018	129.3
2019	0.9
2020	0.0
Thereafter	0.0
Total minimum commitments	582.5
Operating Leases and Other Purchase Obligations [Abstract]
Lease expense	42.1	$ 44.8	$ 45.1
Long-term purchase obligation expense	$ 250.0	$ 250.2	$ 217.2
Connecticut Commercial Campus [Member] | Minimum [Member]
Operating Leases [Abstract]
Remaining operating lease agreement term	8 months
Connecticut Commercial Campus [Member] | Maximum [Member]
Operating Leases [Abstract]
Remaining operating lease agreement term	15 months
California Headquarters [Member]
Operating Leases, Future Minimum Commitments [Abstract]
Total minimum commitments	$ 6.5
California Office Space [Member]
Operating Leases, Future Minimum Commitments [Abstract]
Total minimum commitments	$ 74.1
Litigation Related to Military Family Life Consultants [Member]
Commitments and Contingencies [Line Items]
Number of pending litigations | actions	3
Litigation Relating to the Merger [Member]
Operating Leases and Other Purchase Obligations [Abstract]
Number of Purported Company stockholders | Plaintiff				2
Number of Putative Class Action Lawsuits | actions					2
Pharmacy and Health Quality Services [Member]
Long-Term Purchase Obligations [Abstract]
Long-term purchase commitment, amount	$ 142.8
Pharmacy and Health Quality Services [Member] | Minimum [Member]
Long-Term Purchase Obligations [Abstract]
Remaining long term purchase obligation term	1 year
Pharmacy and Health Quality Services [Member] | Maximum [Member]
Long-Term Purchase Obligations [Abstract]
Remaining long term purchase obligation term	3 years
IT Infrastructure Management Services [Member]
Long-Term Purchase Obligations [Abstract]
Long-term purchase commitment, amount	$ 50.6
Remaining long term purchase obligation term	1 year
Software Applications Development Services [Member]
Long-Term Purchase Obligations [Abstract]
Long-term purchase commitment, amount	$ 225.5
Remaining long term purchase obligation term	3 years
Claims Processing Services [Member]
Long-Term Purchase Obligations [Abstract]
Long-term purchase commitment, amount	$ 19.8
Remaining long term purchase obligation term	1 year