Investment Securities (Other long-term investments) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other Investments	$ 320.9	$ 288.9
Partnership investments [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other Investments	23.5	26.6
Hedge and private equity funds included in other long-term investments
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other Investments	241.9	239.0
Limited Liability Company [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other Investments	50.1	20.3
Other
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other Investments	5.2	3.1
Forward Contracts
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other Investments	$ 0.2	$ (0.1)