Investment Securities (Gains And Losses, Including OTTI, Recognized In Statement Of Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investments [Abstract]
Equity securities gains (losses)	$ 7,168	$ 11,875	$ 13,471
Noncredit-related losses on securities not expected to be sold (recognized in other comprehensive income)	0	0	0
Investment securities, Held-to-maturity, Gross gains	12	1	18
Investment securities Held-to-maturity, Gross losses	0	0	27
Investment securities, Available-for-sale, Gross gains	120	8,443	92,525
Investment securities, Available-for-sale, Gross losses	30	147,656	83,815
Other noninterest-bearing investments, Nonmarketable equity securities, Gross gains	21,176	25,045	23,706
Other noninterest-bearing investments, Nonmarketable equity securities, Gross losses	14,008	12,693	8,544
Total investment securities and other noninterest-bearing investments, Gross gains	21,308	33,489	116,249
Total investment securities and other noninterest-bearing investments, Gross losses	14,038	160,349	92,386
Net losses	7,270	(126,860)	23,863
Net impairment losses on investment securities	0	0	(27)
Fixed income securities gains (losses), net	$ 102	$ (138,735)	$ 10,419