Derivative Financial Instruments (Unrealized And Realized Gains (Losses) On Derivative Contracts (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses)	$ 51,869	$ (82,979)
Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses)	(42,793)	(5,118)
Foreign Exchange Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses)	15,172	6,067
Equity Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses)	71,041	(96,236)
Commodity Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses)	14,491	16,186
Credit Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses)	$ (6,042)	$ (3,878)