Derivatives (Gains/(Losses) on Derivatives Associated with Interest Rate Risk Management Activities) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Customer Interest Rate Contracts Hedging [Member] | Hedging Instruments And Hedged Items [Member] | Customer Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) Related to Interest Rate Derivatives	[1]	$ (3,276)	$ 12,559
Customer Interest Rate Contracts Hedging [Member] | Hedging Instruments And Hedged Items [Member] | Offsetting Upstream Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) Related to Interest Rate Derivatives	[1]	3,276	(12,559)
Debt Hedging [Member] | Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) Related to Interest Rate Derivatives	[1]	(2,800)	17,037
Debt Hedging [Member] | Hedged Items [Member] | Term Borrowings [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) related to term borrowings	[1],[2]	$ 2,733	$ (16,745)

[1] Gains/losses included in the All other expense section of the Consolidated Condensed Statements of Income.

[2] Represents gains and losses attributable to changes in fair value due to interest rate risk as designated in ASC 815-20 hedging relationships