Derivative Instruments And Hedging Strategies (Recognized Gains Losses On Derivative Instruments Not Designated As Hedging Instruments) (Details) (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Derivative [Line Items]
Derivative gains (losses), net	$ (35,725)	$ (230)
Options On Equities And Equity Indices [Member]
Derivative [Line Items]
Derivative gains (losses), net	2,725	1,434
Forward Currency Exchange, Option And Future Contracts [Member]
Derivative [Line Items]
Derivative gains (losses), net	990	505
Interest Rate Swap Agreements [Member]
Derivative [Line Items]
Derivative gains (losses), net	(2,489)	(4,035)
Commodity Swap, Option And Future Contracts, Exchange Traded [Member]
Derivative [Line Items]
Derivative gains (losses), net	(8,818)	898
Commodity Swap, Option And Future Contracts, Non-Exchange traded [Member]
Derivative [Line Items]
Derivative gains (losses), net	1,293	3,048
U.S. Treasury Notes, Rate-Locks And Bond Future And Option Contracts [Member]
Derivative [Line Items]
Derivative gains (losses), net	$ (29,426)	$ (2,080)