SEGMENT INFORMATION (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting, Asset Reconciling Item [Line Items]
Net interest income (expense)	$ 7,143	$ 6,712	$ 2,946
Rental income on operating lease equipment	1,048	971	864
All other noninterest income	1,567	11,104	1,272
Total noninterest income	2,615	12,075	2,136
Total income	9,758	18,787	5,082
Depreciation on operating lease equipment	394	371	345
Maintenance and other operating lease expenses	219	222	189
Personnel cost	3,078	2,636	1,408
Acquisition-related expenses	210	470	231
All other noninterest expense	1,834	1,636	902
Total noninterest expense	5,735	5,335	3,075
Provision for credit losses	431	1,375	645
Income (loss) before income taxes	3,592	12,077	1,362
Income tax expense	815	611	264
Net income	2,777	11,466	1,098
Loans and leases	140,221	133,302	70,781
Operating lease equipment, net	9,323	8,746	8,156
Deposits	155,229	145,854	89,408
Operating Segments | General Bank
Segment Reporting, Asset Reconciling Item [Line Items]
Net interest income (expense)	2,980	2,580	1,830
Rental income on operating lease equipment	0	0	0
All other noninterest income	612	526	483
Total noninterest income	612	526	483
Total income	3,592	3,106	2,313
Depreciation on operating lease equipment	0	0	0
Maintenance and other operating lease expenses	0	0	0
Personnel cost	787	725	549
Acquisition-related expenses	0	0	0
All other noninterest expense	1,244	1,114	909
Total noninterest expense	2,031	1,839	1,458
Provision for credit losses	153	77	11
Income (loss) before income taxes	1,408	1,190	844
Income tax expense	362	319	214
Net income	1,046	871	630
Loans and leases	66,768	62,832	43,212
Operating lease equipment, net	0	0	0
Deposits	73,062	68,729	67,894
Operating Segments | Commercial Bank
Segment Reporting, Asset Reconciling Item [Line Items]
Net interest income (expense)	1,100	1,015	884
Rental income on operating lease equipment	227	231	212
All other noninterest income	315	329	306
Total noninterest income	542	560	518
Total income	1,642	1,575	1,402
Depreciation on operating lease equipment	185	180	169
Maintenance and other operating lease expenses	0	0	0
Personnel cost	233	194	171
Acquisition-related expenses	0	0	0
All other noninterest expense	493	450	405
Total noninterest expense	911	824	745
Provision for credit losses	144	517	121
Income (loss) before income taxes	587	234	536
Income tax expense	147	69	128
Net income	440	165	408
Loans and leases	33,197	30,936	27,491
Operating lease equipment, net	750	780	723
Deposits	3,283	3,228	3,219
Operating Segments | SVB Commercial
Segment Reporting, Asset Reconciling Item [Line Items]
Net interest income (expense)	2,274	1,647	0
Rental income on operating lease equipment	0	0	0
All other noninterest income	565	430	0
Total noninterest income	565	430	0
Total income	2,839	2,077	0
Depreciation on operating lease equipment	0	0	0
Maintenance and other operating lease expenses	0	0	0
Personnel cost	530	401	0
Acquisition-related expenses	0	0	0
All other noninterest expense	1,023	883	0
Total noninterest expense	1,553	1,284	0
Provision for credit losses	134	65	0
Income (loss) before income taxes	1,152	728	0
Income tax expense	295	184	0
Net income	857	544	0
Loans and leases	40,194	39,511	0
Operating lease equipment, net	0	0	0
Deposits	36,637	34,730	0
Operating Segments | Rail
Segment Reporting, Asset Reconciling Item [Line Items]
Net interest income (expense)	(186)	(143)	(80)
Rental income on operating lease equipment	821	740	652
All other noninterest income	15	5	4
Total noninterest income	836	745	656
Total income	650	602	576
Depreciation on operating lease equipment	209	191	176
Maintenance and other operating lease expenses	219	222	189
Personnel cost	25	22	20
Acquisition-related expenses	0	0	0
All other noninterest expense	50	45	42
Total noninterest expense	503	480	427
Provision for credit losses	0	0	0
Income (loss) before income taxes	147	122	149
Income tax expense	36	32	37
Net income	111	90	112
Loans and leases	62	23	78
Operating lease equipment, net	8,573	7,966	7,433
Deposits	18	13	15
Corporate
Segment Reporting, Asset Reconciling Item [Line Items]
Net interest income (expense)	975	1,613	312
Rental income on operating lease equipment	0	0	0
All other noninterest income	60	9,814	479
Total noninterest income	60	9,814	479
Total income	1,035	11,427	791
Depreciation on operating lease equipment	0	0	0
Maintenance and other operating lease expenses	0	0	0
Personnel cost	1,503	1,294	668
Acquisition-related expenses	210	470	231
All other noninterest expense	(976)	(856)	(454)
Total noninterest expense	737	908	445
Provision for credit losses	0	716	513
Income (loss) before income taxes	298	9,803	(167)
Income tax expense	(25)	7	(115)
Net income	323	9,796	(52)
Loans and leases	0	0	0
Operating lease equipment, net	0	0	0
Deposits	$ 42,229	$ 39,154	$ 18,280