Business Segment Information - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Segment Reporting Information [Line Items]
Net interest income (expense)	$ 1,990	$ 795	$ 4,801	$ 2,144
(Benefit) provision for credit losses	192	60	1,126	566
Net interest income after provision for credit losses	1,798	735	3,675	1,578
Noninterest income	615	433	11,532	1,707
Noninterest expense	1,416	760	3,843	2,315
Income (loss) before income taxes	997	408	11,364	970
Income tax expense (benefit)	245	93	412	129
Net income	752	315	10,952	841
Loans and leases	133,202	69,790	133,202	69,790	$ 70,781
Deposits	146,233	87,553	146,233	87,553	89,408
Operating lease equipment, net	8,661	7,984	8,661	7,984	$ 8,156
Operating Segments | General Banking
Segment Reporting Information [Line Items]
Net interest income (expense)	625	495	1,790	1,400
(Benefit) provision for credit losses	7	2	48	(7)
Net interest income after provision for credit losses	618	493	1,742	1,407
Noninterest income	125	118	362	371
Noninterest expense	411	400	1,192	1,192
Income (loss) before income taxes	332	211	912	586
Income tax expense (benefit)	91	55	228	143
Net income	241	156	684	443
Loans and leases	46,077	41,693	46,077	41,693
Deposits	101,021	82,731	101,021	82,731
Operating lease equipment, net	0	0	0	0
Operating Segments | Commercial Banking
Segment Reporting Information [Line Items]
Net interest income (expense)	249	230	744	641
(Benefit) provision for credit losses	132	58	353	60
Net interest income after provision for credit losses	117	172	391	581
Noninterest income	139	133	420	376
Noninterest expense	205	186	615	555
Income (loss) before income taxes	51	119	196	402
Income tax expense (benefit)	14	24	55	90
Net income	37	95	141	312
Loans and leases	30,220	28,023	30,220	28,023
Deposits	3,370	3,682	3,370	3,682
Operating lease equipment, net	739	736	739	736
Operating Segments | Silicon Valley Banking
Segment Reporting Information [Line Items]
Net interest income (expense)	635	0	1,335	0
(Benefit) provision for credit losses	56	0	9	0
Net interest income after provision for credit losses	579	0	1,326	0
Noninterest income	151	0	334	0
Noninterest expense	514	0	1,139	0
Income (loss) before income taxes	216	0	521	0
Income tax expense (benefit)	59	0	140	0
Net income	157	0	381	0
Loans and leases	56,864	0	56,864	0
Deposits	39,970	0	39,970	0
Operating lease equipment, net	0	0	0	0
Operating Segments | Rail
Segment Reporting Information [Line Items]
Net interest income (expense)	(40)	(20)	(101)	(58)
(Benefit) provision for credit losses	0	0	0	0
Net interest income after provision for credit losses	(40)	(20)	(101)	(58)
Noninterest income	194	170	549	493
Noninterest expense	116	110	357	320
Income (loss) before income taxes	38	40	91	115
Income tax expense (benefit)	10	10	23	28
Net income	28	30	68	87
Loans and leases	41	74	41	74
Deposits	12	14	12	14
Operating lease equipment, net	7,922	7,248	7,922	7,248
Corporate
Segment Reporting Information [Line Items]
Net interest income (expense)	521	90	1,033	161
(Benefit) provision for credit losses	(3)	0	716	513
Net interest income after provision for credit losses	524	90	317	(352)
Noninterest income	6	12	9,867	467
Noninterest expense	170	64	540	248
Income (loss) before income taxes	360	38	9,644	(133)
Income tax expense (benefit)	71	4	(34)	(132)
Net income	289	34	9,678	(1)
Loans and leases	0	0	0	0
Deposits	1,860	1,126	1,860	1,126
Operating lease equipment, net	$ 0	$ 0	$ 0	$ 0