Operating Segments - Schedule of Financial Data for Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Average interest earning assets	$ 48,891,230	$ 37,907,414	$ 44,609,968	$ 37,648,256
Interest income	452,947	333,648	793,405	665,446
Interest expense	34,787	32,741	57,576	71,872
Net interest income	418,160	300,907	735,829	593,574
Provision for credit losses	43,998	8,747	47,555	17,403
Net Interest Income After Provision for Credit Losses	374,162	292,160	688,274	576,171
Non-interest income	58,533	43,126	97,803	74,359
Non-interest expense	299,730	171,893	497,070	332,106
Internal transfer expense (income)	0	0	0	0
Income Before Income Taxes	$ 132,965	$ 163,393	$ 289,007	$ 318,424
Return on average interest earning assets (pre-tax)	1.09%	1.72%	1.30%	1.69%
Consumer Lending | Operating Segments
Segment Reporting Information [Line Items]
Average interest earning assets	$ 7,967,305	$ 7,150,137	$ 7,848,764	$ 7,099,973
Interest income	63,137	59,419	122,596	120,264
Interest expense	4,723	5,192	7,930	11,607
Net interest income	58,414	54,227	114,666	108,657
Provision for credit losses	5,402	711	7,275	(1,924)
Net Interest Income After Provision for Credit Losses	53,012	53,516	107,391	110,581
Non-interest income	17,086	21,915	30,903	35,600
Non-interest expense	18,791	19,792	35,359	39,641
Internal transfer expense (income)	37,629	19,862	66,276	39,364
Income Before Income Taxes	$ 13,678	$ 35,777	$ 36,659	$ 67,176
Return on average interest earning assets (pre-tax)	0.69%	2.00%	0.93%	1.89%
Commercial Lending | Operating Segments
Segment Reporting Information [Line Items]
Average interest earning assets	$ 34,549,982	$ 25,485,161	$ 30,743,387	$ 25,509,061
Interest income	352,440	255,895	610,346	508,231
Interest expense	19,735	18,467	31,062	41,702
Net interest income	332,705	237,428	579,284	466,529
Provision for credit losses	38,310	8,066	39,937	19,715
Net Interest Income After Provision for Credit Losses	294,395	229,362	539,347	446,814
Non-interest income	14,425	9,819	31,305	17,533
Non-interest expense	24,448	27,241	49,533	52,772
Internal transfer expense (income)	157,365	71,207	257,281	141,790
Income Before Income Taxes	$ 127,007	$ 140,733	$ 263,838	$ 269,785
Return on average interest earning assets (pre-tax)	1.47%	2.21%	1.72%	2.12%
Treasury and Corporate Other | Operating Segments
Segment Reporting Information [Line Items]
Return on average interest earning assets (pre-tax)		(1.00%)
Treasury and Corporate Other | Treasury and Corporate Other
Segment Reporting Information [Line Items]
Average interest earning assets	$ 6,373,943	$ 5,272,116	$ 6,017,817	$ 5,039,222
Interest income	37,370	18,334	60,463	36,951
Interest expense	10,329	9,082	18,584	18,563
Net interest income	27,041	9,252	41,879	18,388
Provision for credit losses	286	(30)	343	(388)
Net Interest Income After Provision for Credit Losses	26,755	9,282	41,536	18,776
Non-interest income	27,022	11,392	35,595	21,226
Non-interest expense	256,491	124,860	412,178	239,693
Internal transfer expense (income)	(194,994)	(91,069)	(323,557)	(181,154)
Income Before Income Taxes	$ (7,720)	$ (13,117)	$ (11,490)	$ (18,537)
Return on average interest earning assets (pre-tax)	(0.48%)		(0.38%)	(0.74%)