Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Net income for the period	$ 90,437	$ 92,025
Other comprehensive income, net of tax:
Unrealized holding gains on investment securities	32,168	486
Reclassification of HTM securities to AFS Securities	0	10,938
Reclassification to earnings for realized net fixed income securities losses (gains)	(17)	148
Net unrealized gains (losses) on other noninterest-bearing investments	430	(364)
Net unrealized holding gains on derivative instruments	12,901	2,553
Reclassification adjustment for increase in interest income recognized in earnings on derivatives instruments	(1,858)	(629)
Pension and Postretirement	665	0
Other comprehensive income	42,959	13,132
Comprehensive income	133,396	105,157
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Other comprehensive income, net of tax:
Other comprehensive income	$ (665)	$ 0