Operating Segments - Schedule of Financial Data for Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Average interest earning assets	$ 50,531,242	$ 38,332,874	$ 46,605,417	$ 37,902,547
Interest income	536,728	328,801	1,330,133	994,247
Interest expense	82,736	27,775	140,312	99,647
Net interest income	453,992	301,026	1,189,821	894,600
Provision (credit) for credit losses	2,023	3,531	49,578	20,934
Net Interest Income After Provision for Credit Losses	451,969	297,495	1,140,243	873,666
Non-interest income	56,194	42,431	153,997	116,790
Non-interest expense	261,639	174,922	758,709	507,028
Internal transfer expense (income)	0	0	0	0
Income Before Income Taxes	$ 246,524	$ 165,004	$ 535,531	$ 483,428
Return on average interest earning assets (pre-tax)	1.95%	1.72%	1.53%	1.70%
Consumer Lending | Operating Segments
Segment Reporting Information [Line Items]
Average interest earning assets	$ 8,307,993	$ 7,373,897	$ 7,978,732	$ 7,176,086
Interest income	70,590	58,887	193,186	179,151
Interest expense	12,288	4,032	20,218	15,639
Net interest income	58,302	54,855	172,968	163,512
Provision (credit) for credit losses	7,182	(4,614)	14,457	(6,538)
Net Interest Income After Provision for Credit Losses	51,120	59,469	158,511	170,050
Non-interest income	19,637	11,845	50,540	47,445
Non-interest expense	24,352	13,520	59,711	53,161
Internal transfer expense (income)	26,268	20,662	92,544	60,026
Income Before Income Taxes	$ 20,137	$ 37,132	$ 56,796	$ 104,308
Return on average interest earning assets (pre-tax)	0.97%	2.01%	0.95%	1.94%
Commercial Lending | Operating Segments
Segment Reporting Information [Line Items]
Average interest earning assets	$ 36,033,901	$ 25,324,485	$ 32,551,062	$ 25,465,276
Interest income	425,930	250,866	1,036,276	759,097
Interest expense	53,294	13,795	84,356	55,497
Net interest income	372,636	237,071	951,920	703,600
Provision (credit) for credit losses	(5,347)	8,110	34,590	27,825
Net Interest Income After Provision for Credit Losses	377,983	228,961	917,330	675,775
Non-interest income	23,510	11,611	54,815	29,144
Non-interest expense	31,759	27,504	81,292	80,276
Internal transfer expense (income)	113,932	71,141	371,213	212,931
Income Before Income Taxes	$ 255,802	$ 141,927	$ 519,640	$ 411,712
Return on average interest earning assets (pre-tax)	2.84%	2.24%	2.13%	2.16%
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	$ 6,189,348	$ 5,634,492	$ 6,075,623	$ 5,261,185
Interest income	40,208	19,048	100,671	55,999
Interest expense	17,154	9,948	35,738	28,511
Net interest income	23,054	9,100	64,933	27,488
Provision (credit) for credit losses	188	35	531	(353)
Net Interest Income After Provision for Credit Losses	22,866	9,065	64,402	27,841
Non-interest income	13,047	18,975	48,642	40,201
Non-interest expense	205,528	133,898	617,706	373,591
Internal transfer expense (income)	(140,200)	(91,803)	(463,757)	(272,957)
Income Before Income Taxes	$ (29,415)	$ (14,055)	$ (40,905)	$ (32,592)
Return on average interest earning assets (pre-tax)	(1.90%)		(0.90%)	(0.83%)