Derivative Instrument (Notional Table) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
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	55,000,000	58,000,000
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | GBP
Derivatives Fair Value [Line Items]
Derivative, Notional Amount	42,000,000	40,000,000
Designated as Hedging Instrument [Member] | Net Investment Hedging [Member] | CAD
Derivatives Fair Value [Line Items]
Derivative, Notional Amount	1,175,000,000	900,000,000
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	1,050,000,000
Not Designated as Hedging Instrument [Member] | CAD
Derivatives Fair Value [Line Items]
Derivative, Notional Amount	$ 3,000,000	$ 12,000,000