CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands		Total	Cumulative effect adoption adjustment	Common Stock	Preferred Stock	Capital surplus (reduction)	Retained earnings	Retained earnings Cumulative effect adoption adjustment	Treasury stock	Accumulated other comprehensive income (loss)
Beginning balance at Dec. 31, 2021		$ 5,969,397		$ 1,046	$ 22,143	$ 4,650,182	$ 2,973,745		$ (1,352,650)	$ (325,069)
Increase Decrease In Stockholders Equity
Net income		845,502					845,502
Issuance of stock		4,285				4,285
Dividends declared:
Common stock	[1]	(124,168)					(124,168)
Preferred stock		(1,059)					(1,059)
Common stock purchases	[2]	(637,520)				(5,882)			(631,638)
Stock based compensation		17,663				3,923			13,740
Other comprehensive loss, net of tax		(2,399,262)								(2,399,262)
Ending balance at Sep. 30, 2022		3,674,838		1,046	22,143	4,652,508	3,694,020		(1,970,548)	(2,724,331)
Beginning balance at Dec. 31, 2021		5,969,397		1,046	22,143	4,650,182	2,973,745		(1,352,650)	(325,069)
Increase Decrease In Stockholders Equity
Accounting Standards Update			ASU 2022-02
Ending balance at Dec. 31, 2022		4,093,425	$ 28,752	1,047	22,143	4,790,993	3,834,348	$ 28,752	(2,030,178)	(2,524,928)
Beginning balance at Jun. 30, 2022		4,293,349		1,046	22,143	4,576,478	3,311,951		(1,665,253)	(1,953,016)
Increase Decrease In Stockholders Equity
Net income		422,395					422,395
Issuance of stock		1,550				1,550
Dividends declared:
Common stock	[3]	(39,973)					(39,973)
Preferred stock		(353)					(353)
Common stock purchases	[4]	(231,225)				74,118			(305,343)
Stock based compensation		410				362			48
Other comprehensive loss, net of tax		(771,315)								(771,315)
Ending balance at Sep. 30, 2022		3,674,838		1,046	22,143	4,652,508	3,694,020		(1,970,548)	(2,724,331)
Beginning balance at Dec. 31, 2022		4,093,425	$ 28,752	1,047	22,143	4,790,993	3,834,348	$ 28,752	(2,030,178)	(2,524,928)
Increase Decrease In Stockholders Equity
Net income		446,748					446,748
Issuance of stock		4,717		1		4,716
Dividends declared:
Common stock	[1]	(118,924)					(118,924)
Preferred stock		(1,059)					(1,059)
Common stock purchases		(4,491)							(4,491)
Stock based compensation		17,454				1,655			15,799
Other comprehensive loss, net of tax		(9,014)								(9,014)
Ending balance at Sep. 30, 2023		4,457,608		1,048	22,143	4,797,364	4,189,865		(2,018,870)	(2,533,942)
Beginning balance at Jun. 30, 2023		4,565,009		1,047	22,143	4,795,581	4,093,284		(2,018,611)	(2,328,435)
Increase Decrease In Stockholders Equity
Net income		136,609					136,609
Issuance of stock		1,600		1		1,599
Dividends declared:
Common stock	[3]	(39,675)					(39,675)
Preferred stock		(353)					(353)
Common stock purchases		(250)							(250)
Stock based compensation		175				184			(9)
Other comprehensive loss, net of tax		(205,507)								(205,507)
Ending balance at Sep. 30, 2023		$ 4,457,608		$ 1,048	$ 22,143	$ 4,797,364	$ 4,189,865		$ (2,018,870)	$ (2,533,942)

[1] Dividends declared per common share during the nine months   ended September 30, 2023 - $ 1.65   (2022 - $ 1.65 ).

[2] During the   nine months   ended September   30, 2022,   the Corporation   completed a   $ 400   million   accelerated share   repurchase transaction   with respect to   its common   stock and   entered into   an additional   $ 231   million accelerated   share repurchase   transaction   with respect   to its   common stock. Both were accounted for as a treasury stock transaction.   Refer to Note 18 for additional information.

[3] Dividends declared per common share during the quarter   ended September 30, 2023 - $ 0.55   (2022 - $ 0.55 ).

[4] During July 2022,   the Corporation completed   a $ 400   million accelerated   share repurchase transaction   with respect to   its common stock.   During August 2022, the Corporation   entered into a $ 231   million accelerated share   repurchase transaction with   respect to its common   stock. Both were accounted for as treasury stock transactions. Refer to Note   18 for additional information.