Accumulated Other Comprehensive Income (Schedule Of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance January 1				$ 77,080	$ 331,377
Other comprehensive loss before reclassifications to current earnings				(1,123,536)	(137,270)
Amounts reclassified to current earnings from accumulated other comprehensive income				(1,762)	(10,715)
Current period other comprehensive income (loss), before tax				(1,125,298)	(147,985)
Income tax (expense) benefit				281,324	36,998
Current period other comprehensive income (loss), net of tax		$ (332,494)	$ 51,638	(843,974)	(110,987)
Balance June 30, 2022		(766,894)	220,390	(766,894)	220,390
Unrealized Gains (Losses) on Securities (1)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance January 1	[1]			23,174	263,801
Other comprehensive loss before reclassifications to current earnings	[1]			(1,123,536)	(137,270)
Amounts reclassified to current earnings from accumulated other comprehensive income	[1]			9,582	0
Current period other comprehensive income (loss), before tax	[1]			(1,113,954)	(137,270)
Income tax (expense) benefit	[1]			278,488	34,319
Current period other comprehensive income (loss), net of tax	[1]			(835,466)	(102,951)
Balance June 30, 2022	[1]	(812,292)	160,850	(812,292)	160,850
Pension Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance January 1				(20,668)	(25,118)
Other comprehensive loss before reclassifications to current earnings				0	0
Amounts reclassified to current earnings from accumulated other comprehensive income				860	1,166
Current period other comprehensive income (loss), before tax				860	1,166
Income tax (expense) benefit				(215)	(291)
Current period other comprehensive income (loss), net of tax				645	875
Balance June 30, 2022		(20,023)	(24,243)	(20,023)	(24,243)
Unrealized Gains (Losses) on Cash Flow Hedge Derivatives (2)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance January 1	[2]			74,574	92,694
Other comprehensive loss before reclassifications to current earnings	[2]			0	0
Amounts reclassified to current earnings from accumulated other comprehensive income	[2]			(12,204)	(11,881)
Current period other comprehensive income (loss), before tax	[2]			(12,204)	(11,881)
Income tax (expense) benefit	[2]			3,051	2,970
Current period other comprehensive income (loss), net of tax	[2]			(9,153)	(8,911)
Balance June 30, 2022	[2]	$ 65,421	$ 83,783	$ 65,421	$ 83,783

[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.