Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified		0 Months Ended				0 Months Ended
	Mar. 31, 2014	Sep. 26, 2012 Healthcare Strategies, Inc., Plan [Member] plantiff	Feb. 22, 2011 Healthcare Strategies, Inc., Plan [Member] plantiff	Mar. 31, 2014 Investment purchase commitment	Dec. 31, 2013 Investment purchase commitment	Apr. 11, 2014 Subsequent Event Healthcare Strategies, Inc., Plan [Member]
Loss Contingencies [Line Items]
Off-balance sheet commitment to purchase investments				$ 379.5	$ 466.8
Possible losses in excess of amounts accrued	30.0
Sponsors of retirement plan alleging violation			2
Number of plaintiffs		15,000
Damages sought by plaintiffs						$ 15.0