Fair Value Measurements (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Fair Value, Measurements, Recurring Venture capital investments	Jun. 30, 2014 Fair Value, Measurements, Recurring Venture capital investments	Dec. 31, 2013 Fair Value, Measurements, Recurring Venture capital investments	Sep. 30, 2013 Fair Value, Measurements, Recurring Venture capital investments	Jun. 30, 2013 Fair Value, Measurements, Recurring Venture capital investments	Dec. 31, 2012 Fair Value, Measurements, Recurring Venture capital investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, beginning of period					$ 16.7	$ 21.1	$ 21.9	$ 27.6	$ 23.5	$ 20.3
Unrealized gains included in earnings	0.3	3.8	5.3	10.5
Unrealized losses included in earnings	(3.8)	0	(5.1)	(2.0)
Purchases	0	0.3	0	0.3
Settlements	(0.9)	0	(5.4)	(1.5)
Fair value, end of period					$ 16.7	$ 21.1	$ 21.9	$ 27.6	$ 23.5	$ 20.3