Segment Reporting - Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting Information [Line Items]
Net interest income	$ 728	$ 513	$ 1,388	$ 1,037
Provision for credit losses	(35)	(66)	(54)	(310)
Noninterest income	761	369	1,505	670
Noninterest expense	(653)	(480)	(1,289)	(879)
Income before income tax expense	801	336	1,550	518
Total average loans, amortized cost	49,812	36,512	48,056	35,086
Total average assets	150,717	78,433	137,837	75,420
Total average deposits	133,760	67,917	122,248	64,863
Global Commercial Bank
Segment Reporting Information [Line Items]
Noninterest income	174	133	333	300
SVB Private Bank
Segment Reporting Information [Line Items]
Noninterest income	1	1	2	1
SVB Capital
Segment Reporting Information [Line Items]
Noninterest income	175	21	244	26
SVB Leerink
Segment Reporting Information [Line Items]
Noninterest income	149	164	319	226
Operating segments | Global Commercial Bank
Segment Reporting Information [Line Items]
Net interest income	715	485	1,334	949
Provision for credit losses	(11)	(44)	(56)	(238)
Noninterest income	174	133	333	300
Noninterest expense	(307)	(241)	(585)	(466)
Income before income tax expense	571	333	1,026	545
Total average loans, amortized cost	42,727	30,472	41,016	29,805
Total average assets	131,885	67,936	120,470	64,871
Total average deposits	128,918	65,091	117,655	62,153
Operating segments | SVB Private Bank
Segment Reporting Information [Line Items]
Net interest income	29	19	56	34
Provision for credit losses	(5)	(4)	4	(59)
Noninterest income	1	1	2	1
Noninterest expense	(15)	(10)	(28)	(20)
Income before income tax expense	10	6	34	(44)
Total average loans, amortized cost	5,154	4,036	5,066	3,946
Total average assets	5,199	4,072	5,114	3,982
Total average deposits	3,977	2,120	3,636	2,021
Operating segments | SVB Capital
Segment Reporting Information [Line Items]
Net interest income	0	0	0	0
Provision for credit losses	0	0	0	0
Noninterest income	175	21	244	26
Noninterest expense	(18)	(8)	(34)	(17)
Income before income tax expense	157	13	210	9
Total average loans, amortized cost	0	0	0	0
Total average assets	613	430	595	439
Total average deposits	0	0	0	0
Operating segments | SVB Leerink
Segment Reporting Information [Line Items]
Net interest income	0	0	0	0
Provision for credit losses	0	0	0	0
Noninterest income	149	164	319	226
Noninterest expense	(98)	(109)	(235)	(171)
Income before income tax expense	51	55	84	55
Total average loans, amortized cost	0	0	0	0
Total average assets	729	455	748	469
Total average deposits	0	0	0	0
Other Items
Segment Reporting Information [Line Items]
Net interest income	(16)	9	(2)	54
Provision for credit losses	(19)	(18)	(2)	(13)
Noninterest income	262	50	607	117
Noninterest expense	(215)	(112)	(407)	(205)
Income before income tax expense	12	(71)	196	(47)
Total average loans, amortized cost	1,931	2,004	1,974	1,335
Total average assets	12,291	5,540	10,910	5,659
Total average deposits	$ 865	$ 706	$ 957	$ 689