Regulatory Matters - Capital Ratios for Company and Bank under Federal Regulatory Guidelines (Details) $ in Thousands	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
SVB Financial Group
CET 1 risk-based capital, Actual Capital Ratios	0.1104	0.1258
CET 1 risk-based capital, Required Capital Ratios	7.00%	7.00%
CET 1 risk-based capital, Actual Capital Amounts	$ 7,138,006	$ 5,857,744
CET 1 risk-based capital, Required Capital Amounts	$ 4,527,647	$ 3,260,424
Tier 1 risk-based capital, Actual Capital Ratios	0.1189	0.1343
Tier 1 risk-based capital, Required Capital Ratios	0.085	0.085
Tier 1 risk-based capital, Well Capitalized Capital Ratios	0.060	0.060
Tier 1 risk-based capital, Actual Capital Amounts	$ 7,691,936	$ 6,257,442
Tier 1 risk-based capital, Required Capital Amounts	5,497,857	3,959,086
Tier 1 risk-based capital, Well Capitalized Capital Amounts	$ 3,880,840	$ 2,794,649
Total risk-based capital, Actual Capital Ratios	0.1264	0.1423
Total risk-based capital, Required Capital Ratios	0.105	0.105
Total risk-based capital, Well Capitalized Capital Ratios	0.100	0.100
Total risk-based capital, Actual Capital Amounts	$ 8,175,430	$ 6,630,022
Total risk-based capital, Required Capital Amounts	6,791,470	4,890,636
Total risk-based capital, Well Capitalized Capital Amounts	$ 6,468,066	$ 4,657,748
Tier 1 leverage, Actual Capital Ratios	0.0745	0.0906
Tier 1 leverage, Required Capital Ratios	0.040	0.040
Tier 1 leverage, Actual Capital Amounts	$ 7,691,936	$ 6,257,442
Tier 1 leverage, Required Capital Amounts	$ 4,128,596	$ 2,763,146
Silicon Valley Bank
CET 1 risk-based capital, Actual Capital Ratios	0.1070	0.1112
CET 1 risk-based capital, Required Capital Ratios	7.00%	7.00%
CET 1 risk-based capital, Well Capitalized Capital Ratios	6.50%	6.50%
CET 1 risk-based capital, Actual Capital Amounts	$ 6,530,167	$ 4,949,393
CET 1 risk-based capital, Required Capital Amounts	4,271,642	3,115,151
CET 1 risk-based capital, Well Capitalized Capital Amounts	$ 3,966,525	$ 2,892,640
Tier 1 risk-based capital, Actual Capital Ratios	0.1070	0.1112
Tier 1 risk-based capital, Required Capital Ratios	0.085	0.085
Tier 1 risk-based capital, Well Capitalized Capital Ratios	0.080	0.080
Tier 1 risk-based capital, Actual Capital Amounts	$ 6,530,167	$ 4,949,393
Tier 1 risk-based capital, Required Capital Amounts	5,186,994	3,782,683
Tier 1 risk-based capital, Well Capitalized Capital Amounts	$ 4,881,877	$ 3,560,172
Total risk-based capital, Actual Capital Ratios	0.1149	0.1196
Total risk-based capital, Required Capital Ratios	0.105	0.105
Total risk-based capital, Well Capitalized Capital Ratios	0.100	0.100
Total risk-based capital, Actual Capital Amounts	$ 7,013,630	$ 5,321,850
Total risk-based capital, Required Capital Amounts	6,407,463	4,672,726
Total risk-based capital, Well Capitalized Capital Amounts	$ 6,102,346	$ 4,450,215
Tier 1 leverage, Actual Capital Ratios	0.0643	0.0730
Tier 1 leverage, Required Capital Ratios	0.040	0.040
Tier 1 leverage, Well Capitalized Capital Ratios	0.050	0.050
Tier 1 leverage, Actual Capital Amounts	$ 6,530,167	$ 4,949,393
Tier 1 leverage, Required Capital Amounts	4,060,180	2,713,367
Tier 1 leverage, Well Capitalized Capital Amounts	$ 5,075,225	$ 3,391,709

Common Equity Tier One Capital Required For Capital Adequacy To Risk Weighted Assets

No definition available.

Name:	sivb_CommonEquityTierOneCapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix:	sivb_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Common Equity Tier One Capital Required To Be Well Capitalized To Risk Weighted Assets

+ References

No definition available.

+ Details

Name:	sivb_CommonEquityTierOneCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix:	sivb_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of total capital as defined by regulatory framework.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6490092&loc=d3e47304-110998

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=6490092&loc=d3e47080-110998

+ Details

Name:	us-gaap_Capital
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of minimum total risk-based capital required for capital adequacy as defined by regulatory framework.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826

+ Details

Name:	us-gaap_CapitalRequiredForCapitalAdequacy
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Ratio of minimum total risk-based capital to risk-weighted assets required for capital adequacy as defined by regulatory framework.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826

+ Details

Name:	us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of minimum total risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_CapitalRequiredToBeWellCapitalized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Ratio of minimum total risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio of total risk-based capital to risk-weighted assets as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_CapitalToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of Common Equity Tier 1 risk-based capital as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_CommonEquityTierOneCapital
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Ratio of Common Equity Tier 1 risk-based capital to risk-weighted assets as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_CommonEquityTierOneCapitalRatio
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of minimum Common Equity Tier 1 risk-based capital required for capital adequacy as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_CommonEquityTierOneCapitalRequiredForCapitalAdequacy
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of minimum Common Equity Tier 1 risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_CommonEquityTierOneCapitalRequiredToBeWellCapitalized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of Tier 1 leverage capital as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapital
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of minimum Tier 1 leverage capital required for capital adequacy as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Ratio of minimum Tier 1 leverage capital to average assets required for capital adequacy as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of minimum Tier 1 leverage capital categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Ratio of minimum Tier 1 leverage capital to average assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio of Tier 1 capital to average assets as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalToAverageAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of Tier 1 risk-based capital as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapital
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of minimum Tier 1 risk-based capital required for capital adequacy as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Ratio of minimum Tier 1 risk-based capital to risk-weighted assets required for capital adequacy as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of minimum Tier 1 risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Ratio of minimum Tier 1 risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio of Tier 1 risk-based capital to risk-weighted assets as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	dei_LegalEntityAxis=sivb_SVBFinancialGroupMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=sivb_SiliconValleyBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: