Operating Segments - Schedule of Financial Data for Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information [Line Items]
Average interest earning assets	$ 57,651,650	$ 56,802,565	$ 57,016,790	$ 56,510,997
Interest income	860,549	813,018	2,522,671	2,320,707
Interest expense	450,051	400,600	1,316,940	1,052,504
Net interest income	410,498	412,418	1,205,731	1,268,203
Provision (credit) for credit losses	75,024	9,117	202,294	29,604
Net interest income after provision for credit losses	335,474	403,301	1,003,437	1,238,599
Non-interest income	60,671	58,664	173,299	173,038
Non-interest expense	269,471	267,133	827,278	822,270
Internal transfer expense (income)	0	0	0	0
Income before income taxes	$ 126,674	$ 194,832	$ 349,458	$ 589,367
Return on average interest earning assets (pre-tax)	0.88%	1.37%	0.82%	1.39%
Consumer Banking | Operating Segments
Segment Reporting Information [Line Items]
Average interest earning assets	$ 9,929,693	$ 9,681,379	$ 9,855,089	$ 9,599,359
Interest income	122,419	106,384	354,718	305,025
Interest expense	75,373	65,987	221,246	172,202
Net interest income	47,046	40,397	133,472	132,823
Provision (credit) for credit losses	6,007	(4,568)	13,899	5,368
Net interest income after provision for credit losses	41,039	44,965	119,573	127,455
Non-interest income	26,239	21,035	77,780	59,858
Non-interest expense	24,243	20,796	68,260	65,595
Internal transfer expense (income)	29,709	30,104	91,782	90,460
Income before income taxes	$ 13,326	$ 15,100	$ 37,311	$ 31,258
Return on average interest earning assets (pre-tax)	0.54%	0.62%	0.50%	0.43%
Commercial Banking | Operating Segments
Segment Reporting Information [Line Items]
Average interest earning assets	$ 40,197,270	$ 40,338,035	$ 40,276,379	$ 39,520,794
Interest income	664,261	647,258	1,974,478	1,819,015
Interest expense	305,156	274,377	904,202	708,961
Net interest income	359,105	372,881	1,070,276	1,110,054
Provision (credit) for credit losses	69,031	13,715	188,524	19,561
Net interest income after provision for credit losses	290,074	359,166	881,752	1,090,493
Non-interest income	9,259	13,015	38,051	43,105
Non-interest expense	44,662	40,248	136,653	127,810
Internal transfer expense (income)	121,053	121,878	374,903	372,426
Income before income taxes	$ 133,618	$ 210,055	$ 408,247	$ 633,362
Return on average interest earning assets (pre-tax)	1.33%	2.08%	1.35%	2.14%
Treasury and Corporate Other | Operating Segments
Segment Reporting Information [Line Items]
Average interest earning assets				$ 7,390,844
Interest income				196,667
Interest expense				171,341
Net interest income				25,326
Provision (credit) for credit losses				4,675
Net interest income after provision for credit losses				20,651
Non-interest income				70,075
Non-interest expense				628,865
Internal transfer expense (income)				(462,886)
Income before income taxes				$ (75,253)
Return on average interest earning assets (pre-tax)				(1.36%)
Treasury and Corporate Other | Treasury and Corporate Other
Segment Reporting Information [Line Items]
Average interest earning assets	$ 7,524,687	$ 6,783,151	$ 6,885,322
Interest income	73,869	59,376	193,475
Interest expense	69,522	60,236	191,492
Net interest income	4,347	(860)	1,983
Provision (credit) for credit losses	(14)	(30)	(129)
Net interest income after provision for credit losses	4,361	(830)	2,112
Non-interest income	25,173	24,614	57,468
Non-interest expense	200,566	206,089	622,365
Internal transfer expense (income)	(150,762)	(151,982)	(466,685)
Income before income taxes	$ (20,270)	$ (30,323)	$ (96,100)
Return on average interest earning assets (pre-tax)	(1.08%)	(1.79%)	(1.86%)