Accumulated Other Comprehensive Income (Schedule Of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance				$ (1,086,864)	$ 77,080
Other comprehensive income (loss) before reclassifications to current earnings				(139,560)	(1,598,445)
Amounts reclassified to current earnings from accumulated other comprehensive income				(2,666)	3,214
Current period other comprehensive income (loss), before tax				(142,226)	(1,595,231)
Income tax (expense) benefit				35,556	398,807
Current period other comprehensive income (loss), net of tax		$ (157,239)	$ (352,450)	(106,670)	(1,196,424)
Ending balance		(1,193,534)	(1,119,344)	(1,193,534)	(1,119,344)
Unrealized Gains (Losses) on Securities (1)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	[1]			(1,124,915)	23,174
Other comprehensive income (loss) before reclassifications to current earnings	[1]			(105,030)	(1,594,981)
Amounts reclassified to current earnings from accumulated other comprehensive income	[1]			8,444	20,274
Current period other comprehensive income (loss), before tax	[1]			(96,586)	(1,574,707)
Income tax (expense) benefit	[1]			24,146	393,676
Current period other comprehensive income (loss), net of tax	[1]			(72,440)	(1,181,031)
Ending balance	[1]	(1,197,355)	(1,157,857)	(1,197,355)	(1,157,857)
Pension Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance				(17,186)	(20,668)
Other comprehensive income (loss) before reclassifications to current earnings				0	0
Amounts reclassified to current earnings from accumulated other comprehensive income				983	1,262
Current period other comprehensive income (loss), before tax				983	1,262
Income tax (expense) benefit				(245)	(315)
Current period other comprehensive income (loss), net of tax				738	947
Ending balance		(16,448)	(19,721)	(16,448)	(19,721)
Unrealized Gains (Losses) on Cash Flow Hedge Derivatives (2)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	[2]			55,237	74,574
Other comprehensive income (loss) before reclassifications to current earnings	[2]			(34,530)	(3,464)
Amounts reclassified to current earnings from accumulated other comprehensive income	[2]			(12,093)	(18,322)
Current period other comprehensive income (loss), before tax	[2]			(46,623)	(21,786)
Income tax (expense) benefit	[2]			11,655	5,446
Current period other comprehensive income (loss), net of tax	[2]			(34,968)	(16,340)
Ending balance	[2]	$ 20,269	$ 58,234	$ 20,269	$ 58,234

[1] The pre-tax amounts reclassified from accumulated other comprehensive income to current earnings are included in "investment securities gains (losses), net" in the consolidated statements of income.

[2] The pre-tax amounts reclassified from accumulated other comprehensive income to current earnings are included in "interest and fees on loans" in the consolidated statements of income.