Fair Value Disclosures (Summary Of Gains (Losses) Due To Changes In Instrument Specific Credit Risk For Loans and Other Receivables And Loan Commitments Measured At Fair Value Under Fair Value Option) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Financial Instruments [Line Items]
Loans and other receivables	$ 14,002	$ 24,846	$ 7,495	$ 27,715
Financial Instruments Sold
Financial Instruments [Line Items]
Loans	(2,708)	3,436	(2,467)	(7,286)
Loan commitments	(1,695)	82	(1,964)	229
Long-term debt
Financial Instruments [Line Items]
Changes in instrument specific credit risk	1,401	5,638	19,986	(14,141)
Other changes in fair value	(6,842)	(1,854)	33,626	2,786
Short-term Borrowings
Financial Instruments [Line Items]
Changes in instrument specific credit risk	0	19	0	1
Other changes in fair value	$ 0	$ (2,570)	$ 0	$ (37)