Derivatives Instruments (Notional Table) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | USD
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 57,000,000	$ 57,000,000
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | CAD
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	58,000,000	0
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | GBP
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	40,000,000	0
Designated as Hedging Instrument [Member] | Net Investment Hedging [Member] | CAD
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	900,000,000	600,000,000
Notional Amount of Nonderivative Instruments	250,000,000	250,000,000
Designated as Hedging Instrument [Member] | Net Investment Hedging [Member] | GBP
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	350,000,000	350,000,000
Notional Amount of Nonderivative Instruments	1,050,000,000	550,000,000
Not Designated as Hedging Instrument [Member] | CAD
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 12,000,000	$ 0