Derivatives (Gains/(Losses) on Derivatives Associated with Interest Rate Risk Management Activities) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Customer Interest Rate Contracts Hedging | Hedging Instruments And Hedged Items | Customer Interest Rate Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) Related to Interest Rate Derivatives	[1]	$ 4,099	$ 8,154	$ 823	$ 20,713
Customer Interest Rate Contracts Hedging | Hedging Instruments And Hedged Items | Offsetting Upstream Interest Rate Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) Related to Interest Rate Derivatives	[1]	(4,099)	(8,154)	(823)	(20,713)
Debt Hedging | Hedging Instruments | Interest Rate Swap
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) Related to Interest Rate Derivatives	[1]	1,808	6,660	(992)	26,606
Debt Hedging | Hedged Items | Term Borrowings
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) related to term borrowings	[1],[2]	$ (1,804)	$ (6,557)	$ 929	$ (26,211)

[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.