Operating Segments - Schedule of Financial Data for Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Average interest earning assets	$ 56,618,797	$ 55,362,790
Interest income	828,656	720,230
Interest expense	435,108	284,210
Net interest income	393,548	436,020
Provision (credit) for credit losses	45,200	14,437
Net interest income after provision for credit losses	348,348	421,583
Non-interest income	61,415	54,299
Non-interest expense	280,310	272,166
Internal transfer expense (income)	0	0
Income (loss) before income taxes	$ 129,453	$ 203,716
Return on average interest earning assets (pre-tax)	0.91%	1.47%
Consumer Banking | Operating Segments
Segment Reporting Information [Line Items]
Average interest earning assets	$ 9,795,462	$ 9,476,112
Interest income	113,631	95,963
Interest expense	73,173	46,476
Net interest income	40,458	49,487
Provision (credit) for credit losses	3,072	6,444
Net interest income after provision for credit losses	37,386	43,043
Non-interest income	26,546	17,882
Non-interest expense	18,651	19,633
Internal transfer expense (income)	33,111	28,968
Income (loss) before income taxes	$ 12,170	$ 12,324
Return on average interest earning assets (pre-tax)	0.50%	0.52%
Commercial Banking | Operating Segments
Segment Reporting Information [Line Items]
Average interest earning assets	$ 40,451,129	$ 38,383,259
Interest income	657,922	559,263
Interest expense	302,174	188,253
Net interest income	355,748	371,010
Provision (credit) for credit losses	42,202	3,006
Net interest income after provision for credit losses	313,546	368,004
Non-interest income	17,994	15,747
Non-interest expense	36,288	35,723
Internal transfer expense (income)	136,631	117,461
Income (loss) before income taxes	$ 158,621	$ 230,567
Return on average interest earning assets (pre-tax)	1.57%	2.40%
Treasury and Corporate Other | Treasury and Corporate Other
Segment Reporting Information [Line Items]
Average interest earning assets	$ 6,372,206	$ 7,503,419
Interest income	57,103	65,004
Interest expense	59,761	49,481
Net interest income	(2,658)	15,523
Provision (credit) for credit losses	(74)	4,987
Net interest income after provision for credit losses	(2,584)	10,536
Non-interest income	16,875	20,670
Non-interest expense	225,371	216,810
Internal transfer expense (income)	(169,742)	(146,429)
Income (loss) before income taxes	$ (41,338)	$ (39,175)
Return on average interest earning assets (pre-tax)	(2.59%)	(2.09%)