Commitments and Contingencies - Summary (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Investments in affordable housing projects
Other Commitments [Line Items]
Carrying amount	$ 2,088	$ 1,948
Amount of future funding commitments included in carrying amount	919	928
Lending exposure	460	561
Tax credits subject to recapture	523	471
Private equity investments
Other Commitments [Line Items]
Carrying amount	458	471
Amount of future funding commitments not included in carrying amount	$ 331	$ 143

Lending commitments to Affordable Housing Projects

No definition available.

Name:	bbt_AffordableHousingProjectsLendingCommitments
Namespace Prefix:	bbt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Tax Credits Subject To Recapture Related To Affordable Housing Projects

+ References

No definition available.

+ Details

Name:	bbt_TaxCreditsSubjectToRecaptureRelatedToAffordableHousingProjects
Namespace Prefix:	bbt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in qualified affordable housing projects.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=114775393&loc=SL49122993-202985

+ Details

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

- Definition

Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

+ References

No definition available.

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Amount of commitment or contingent commitments to qualified affordable housing project investments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=114775393&loc=SL49122993-202985

+ Details

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

- Definition

Aggregate carrying value of owned private equity or other securities for which a quoted market price is not readily determinable, the value of which has been determined by management based upon fair value methods, including pricing of similar securities and valuation techniques and is included in the schedule of financial condition or the balance sheet.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher SEC
-Name Rule 15c3-1
-Number 240
-Section 15c3-1

+ Details

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

- Details

Name:	us-gaap_OtherCommitmentsAxis=bbt_AffordablehousingprojectsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherCommitmentsAxis=us-gaap_PrivateEquityFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: