Federal Funds Sold and Securities Borrowed or Purchased Under Agreements to Resell - Additional Information (Details) (USD $)	Jun. 30, 2013	Dec. 31, 2012
Assets Sold under Agreements to Repurchase [Line Items]
Federal Funds Sold	$ 69,000,000	$ 29,000,000
Collateral Requirements Minimum Percentage Collateral To Fair Value Of Securities Purchased Under Repurchase Agreements	95.00%
Collateral Requirements Maximum Percentage Collateral To Fair Value Of Securities Purchased Under Repurchase Agreements	110.00%
Fair Value of Securities Received as Collateral that Can be Resold or Repledged	1,000,000,000	1,100,000,000
Fair Value of Securities Received as Collateral that Have Been Resold or Repledged	254,000,000	246,000,000
Trading Securities Pledged as Collateral	926,000,000	727,000,000
Amount of Repurchase Agreements Secured by Trading Assets	$ 934,000,000	$ 703,000,000

Amount of Repurchase Agreements Secured by Trading Assets

No definition available.

Name:	sti_AmountOfRepurchaseAgreementsSecuredByTradingAssets
Namespace Prefix:	sti_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Collateral Requirements Maximum Percentage Collateral To Fair Value Of Securities Purchased or Borrowed Under Repurchase Agreements

+ References

No definition available.

+ Details

Name:	sti_CollateralRequirementsMaximumPercentageCollateralToFairValueOfSecuritiesPurchasedOrBorrowedUnderRepurchaseAgreements
Namespace Prefix:	sti_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Collateral Requirements, Minimum Percentage, Collateral To Fair Value Of Securities Purchased or Borrowed Under Repurchase Agreements

+ References

No definition available.

+ Details

Name:	sti_CollateralRequirementsMinimumPercentageCollateralToFairValueOfSecuritiesPurchasedOrBorrowedUnderRepurchaseAgreements
Namespace Prefix:	sti_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_AssetsSoldUnderAgreementsToRepurchaseLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This is the fair value as of the date of each statement of financial position presented of the collateral that is permitted, by contact or custom, to be sold or re-pledged.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 140

-Paragraph 17

-Subparagraph a(3)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 30

-Section 50

-Paragraph 1A

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=7523297&loc=SL6224234-111729

+ Details

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

- Definition

Fair value as of the balance sheet date of the collateral, or portion thereof, that has been re-pledged, delivered, or otherwise used (generally under repurchase agreements, securities lending agreements or to cover short sales).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 30

-Section 50

-Paragraph 1A

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=7523297&loc=SL6224234-111729

+ Details

Name:	us-gaap_FairValueOfSecuritiesReceivedAsCollateralThatHaveBeenResoldOrRepledged
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount outstanding of funds lent to other depository institutions, securities brokers, or securities dealers in the form of Federal Funds sold; for example, immediately available funds lent under agreements or contracts that mature in one business day or roll over under a continuing contract, regardless of the nature of the transaction or the collateral involved, excluding overnight lending for commercial and industrial purposes. Also include Federal Funds sold under agreements to resell on a gross basis, excluding (1) sales of term Federal Funds, (2) due bills representing purchases of securities or other assets by the reporting bank that have not yet been delivered and similar instruments, (3) resale agreements that mature in more than one business day involving assets other than securities, and (4) yield maintenance dollar repurchase agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.3)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher OTS

-Name Federal Regulation (FR)

-Number Title 12

-Section 563c.102

-Chapter V

-Subsection I

-LegacyDoc This is a non-GAAP reference that was included in the 2009 taxonomy. It will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Article 9

+ Details

Name:	us-gaap_FederalFundsSold
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The fair value of trading securities that serve as collateral for borrowings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 01-6

-Paragraph 13

-Subparagraph i

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=7512638&loc=d3e5086-111524

+ Details

Name:	us-gaap_TradingSecuritiesPledgedAsCollateral
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant