Investment Securities (Other long-term investments) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other Investments	$ 313.0	$ 288.9
Partnership investments [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other Investments	24.5	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	260.8	239.0
Limited Liability Company [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other Investments	22.3	20.3
Other
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other Investments	5.3	3.1
Forward Contracts
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other Investments	$ 0.1	$ (0.1)