Operating Segments - Schedule of Financial Data for Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Average interest earning assets	$ 57,351,808	$ 48,891,230	$ 56,362,794	$ 44,609,968
Interest income	787,459	452,947	1,507,689	793,405
Interest expense	367,694	34,787	651,904	57,576
Net interest income	419,765	418,160	855,785	735,829
Provision (credit) for credit losses	6,050	43,998	20,487	47,555
Net Interest Income After Provision for Credit Losses	413,715	374,162	835,298	688,274
Non-interest income	60,075	58,533	114,374	97,803
Non-interest expense	282,971	299,730	555,137	497,070
Internal transfer expense (income)	0	0	0	0
Income Before Income Taxes	$ 190,819	$ 132,965	$ 394,535	$ 289,007
Return on average interest earning assets (pre-tax)	1.33%	1.09%	1.40%	1.30%
Consumer Banking | Operating Segments
Segment Reporting Information [Line Items]
Average interest earning assets	$ 8,904,483	$ 7,967,305	$ 8,836,859	$ 7,848,764
Interest income	90,602	63,137	175,918	122,596
Interest expense	55,198	4,723	98,204	7,930
Net interest income	35,404	58,414	77,714	114,666
Provision (credit) for credit losses	3,492	5,402	9,936	7,275
Net Interest Income After Provision for Credit Losses	31,912	53,012	67,778	107,391
Non-interest income	25,529	17,086	39,819	30,903
Non-interest expense	23,223	18,791	41,472	35,359
Internal transfer expense (income)	22,018	37,629	52,901	66,276
Income Before Income Taxes	$ 12,200	$ 13,678	$ 13,224	$ 36,659
Return on average interest earning assets (pre-tax)	0.55%	0.69%	0.30%	0.93%
Commercial Banking | Operating Segments
Segment Reporting Information [Line Items]
Average interest earning assets	$ 40,553,454	$ 34,549,982	$ 39,826,630	$ 30,743,387
Interest income	624,569	352,440	1,194,479	610,346
Interest expense	250,871	19,735	442,594	31,062
Net interest income	373,698	332,705	751,885	579,284
Provision (credit) for credit losses	2,840	38,310	5,846	39,937
Net Interest Income After Provision for Credit Losses	370,858	294,395	746,039	539,347
Non-interest income	14,361	14,425	30,108	31,305
Non-interest expense	35,365	24,448	71,088	49,533
Internal transfer expense (income)	102,395	157,365	233,990	257,281
Income Before Income Taxes	$ 247,459	$ 127,007	$ 471,069	$ 263,838
Return on average interest earning assets (pre-tax)	2.44%	1.47%	2.37%	1.72%
Treasury and Corporate Other | Treasury and Corporate Other
Segment Reporting Information [Line Items]
Average interest earning assets	$ 7,893,871	$ 6,373,943	$ 7,699,305	$ 6,017,817
Interest income	72,288	37,370	137,292	60,463
Interest expense	61,625	10,329	111,106	18,584
Net interest income	10,663	27,041	26,186	41,879
Provision (credit) for credit losses	(282)	286	4,705	343
Net Interest Income After Provision for Credit Losses	10,945	26,755	21,481	41,536
Non-interest income	20,185	27,022	44,447	35,595
Non-interest expense	224,383	256,491	442,577	412,178
Internal transfer expense (income)	(124,413)	(194,994)	(286,891)	(323,557)
Income Before Income Taxes	$ (68,840)	$ (7,720)	$ (89,758)	$ (11,490)
Return on average interest earning assets (pre-tax)	(3.49%)	(0.48%)	(2.33%)	(0.38%)