Interim Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Impact of adopting ASC 326	Common Stock	Noncumulative Preferred Stock	Preferred Stock	Preferred Stock Noncumulative Preferred Stock	Common Stock	Common Stock Common Stock	Additional Paid-in Capital	Additional Paid-in Capital Common Stock	Retained Earnings	Retained Earnings Impact of adopting ASC 326	Accumulated Other Comprehensive Income	Total SVBFG Stockholders’ Equity	Total SVBFG Stockholders’ Equity Impact of adopting ASC 326	Total SVBFG Stockholders’ Equity Common Stock	Total SVBFG Stockholders’ Equity Noncumulative Preferred Stock	Noncontrolling Interests
Balance (in shares) at Dec. 31, 2019							51,655,607
Balance, beginning of period, net of tax at Dec. 31, 2019	$ 6,621				$ 340		$ 0		$ 1,470		$ 4,576		$ 84	$ 6,470				$ 151
Balance, beginning of period, net of tax (Day one impact for adoption of ASC 326) at Dec. 31, 2019		$ (35)										$ (35)			$ (35)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under employee benefit plans, net of restricted stock cancellations (in shares)							329,330
Common stock issued under employee benefit plans, net of restricted stock cancellations	14						$ 0		14					14
Net income	381													369				12
Capital calls and distributions, net	(14)																	(14)
Other comprehensive income, net of tax	530												530	530
Share-based compensation, net	39								39					39
Common stock repurchases (in shares)							(244,223)
Common stock repurchases	(60)						$ 0				(60)			(60)
Dividends on preferred stock	(8)										(8)			(8)
Balance (in shares) at Jun. 30, 2020							51,740,714
Balance, end of period, net of tax at Jun. 30, 2020	7,468				340		$ 0		1,523		4,842		614	7,319				149
Balance (in shares) at Mar. 31, 2020							51,490,342
Balance, beginning of period, net of tax at Mar. 31, 2020	7,182				340		$ 0		1,489		4,613		592	7,034				148
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under employee benefit plans, net of restricted stock cancellations (in shares)							250,372
Common stock issued under employee benefit plans, net of restricted stock cancellations	14								14					14
Net income	248										234			234				14
Capital calls and distributions, net	(13)																	(13)
Other comprehensive income, net of tax	22												22	22
Share-based compensation, net	20								20					20
Dividends on preferred stock	(5)										(5)			(5)
Balance (in shares) at Jun. 30, 2020							51,740,714
Balance, end of period, net of tax at Jun. 30, 2020	7,468				340		$ 0		1,523		4,842		614	7,319				149
Balance (in shares) at Dec. 31, 2020							51,888,463
Balance, beginning of period, net of tax at Dec. 31, 2020	8,433				340		$ 0		1,585		5,672		623	8,220				213
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under employee benefit plans, net of restricted stock cancellations (in shares)							341,844
Common stock issued under employee benefit plans, net of restricted stock cancellations	(3)						$ 0		(3)					(3)
Issuance of stock			$ 1,118	$ 1,724				$ 0		$ 1,118						$ 1,118	$ 1,724
Issuance of stock (in shares)						1,724,000,000		2,300,000
Net income	1,190										1,052			1,052				138
Capital calls and distributions, net	(51)																	(51)
Other comprehensive income, net of tax	(481)												(481)	(481)
Share-based compensation, net	55								55					55
Dividends on preferred stock	(18)										(18)			(18)
Balance (in shares) at Jun. 30, 2021							54,530,307
Balance, end of period, net of tax at Jun. 30, 2021	11,967				2,064		$ 0		2,755		6,706		142	11,667				300
Balance (in shares) at Mar. 31, 2021							54,001,797
Balance, beginning of period, net of tax at Mar. 31, 2021	10,121				1,079		$ 0		2,591		6,204		21	9,895				226
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under employee benefit plans, net of restricted stock cancellations (in shares)							228,510
Common stock issued under employee benefit plans, net of restricted stock cancellations	(5)								(5)					(5)
Issuance of stock			$ 146	$ 985				$ 0		$ 146						$ 146	$ 985
Issuance of stock (in shares)						985,000,000		300,000
Net income	628										515			515				113
Capital calls and distributions, net	(39)																	(39)
Other comprehensive income, net of tax	121												121	121
Share-based compensation, net	28								28					28
Dividends on preferred stock	(13)										(13)			(13)
Balance (in shares) at Jun. 30, 2021							54,530,307
Balance, end of period, net of tax at Jun. 30, 2021	$ 11,967				$ 2,064		$ 0		$ 2,755		$ 6,706		$ 142	$ 11,667				$ 300