Business Segments - Schedule Of Operating Results And Other Key Financial Measures For The Individual Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Segment Reporting Information
Net interest income (loss) before provision for credit losses	$ 572,722	$ 570,813	$ 1,691,090	$ 1,737,420
Provision for (reversal of) credit losses	42,000	42,000	104,000	88,000
Noninterest income	84,761	76,752	248,422	215,361
Noninterest expense	226,166	252,014	709,475	732,250
INCOME BEFORE INCOME TAXES	389,317	353,551	1,126,037	1,132,531
Segment net income (loss)	299,166	287,738	872,471	922,208
Segment assets	74,483,720	68,289,458	74,483,720	68,289,458	$ 69,612,884
Consumer and Business Banking
Segment Reporting Information
Net interest income (loss) before provision for credit losses	290,884	314,521	880,316	922,845
Provision for (reversal of) credit losses	5,927	2,563	5,246	29,037
Noninterest income	27,970	25,119	80,288	77,191
Noninterest expense	112,006	105,557	337,836	318,947
INCOME BEFORE INCOME TAXES	200,921	231,520	617,522	652,052
Segment net income (loss)	141,532	163,513	434,992	460,516
Segment assets	19,650,183	18,925,029	19,650,183	18,925,029
Commercial Banking
Segment Reporting Information
Net interest income (loss) before provision for credit losses	288,704	284,787	855,607	825,122
Provision for (reversal of) credit losses	36,934	35,506	99,996	56,093
Noninterest income	45,577	42,166	141,634	128,306
Noninterest expense	93,602	86,613	296,252	255,709
INCOME BEFORE INCOME TAXES	203,745	204,834	600,993	641,626
Segment net income (loss)	143,218	144,489	423,407	453,360
Segment assets	35,714,691	34,028,487	35,714,691	34,028,487
Treasury and Other
Segment Reporting Information
Net interest income (loss) before provision for credit losses	(6,866)	(28,495)	(44,833)	(10,547)
Provision for (reversal of) credit losses	(861)	3,931	(1,242)	2,870
Noninterest income	11,214	9,467	26,500	9,864
Noninterest expense	20,558	59,844	75,387	157,594
INCOME BEFORE INCOME TAXES	(15,349)	(82,803)	(92,478)	(161,147)
Segment net income (loss)	14,416	(20,264)	14,072	8,332
Segment assets	$ 19,118,846	$ 15,335,942	$ 19,118,846	$ 15,335,942