XML 22 R87.htm IDEA: XBRL DOCUMENT
v3.20.1

Commitments, Contingencies, Guarantees, and Others - Litigation (Detail) $ in Millions |  | 1 Months Ended |
--- | --- | --- | ---
Dec. 31, 2019 USD ($) | Oct. 31, 2018 USD ($) | Mar. 31, 2020 USD ($) claim
Loss Contingencies [Line Items] |  |  |
Loss contingency, estimate of possible loss | $ |  |  | $ 1,200
Number of consumer class action cases filed for Cybersecurity Incident | claim |  |  | 73
Anti-money laundering |  |  |
Loss Contingencies [Line Items] |  |  |
Litigation settlement paid | $ |  | $ 100 |
Pending litigation | Interchange litigation |  |  |
Loss Contingencies [Line Items] |  |  |
Litigation settlement, attributable to reporting entity and third party | $ | $ 5,500 |  |
United States |  |  |
Loss Contingencies [Line Items] |  |  |
Number of consumer class action cases filed for Cybersecurity Incident | claim |  |  | 61
Canada |  |  |
Loss Contingencies [Line Items] |  |  |
Number of consumer class action cases filed for Cybersecurity Incident | claim |  |  | 12

X
- Definition Litigation Settlement, Amount Attributable to Reporting Entity and Third Party + References No definition available. + Details
Name: | cof_LitigationSettlementAmountAttributabletoReportingEntityandThirdParty
Namespace Prefix: | cof_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of consumer class action cases filed for Cybersecurity Incident + References No definition available. + Details
Name: | cof_NumberofConsumerClassActionCasesFiledforCybersecurityIncident
Namespace Prefix: | cof_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount awarded to other party in judgment or settlement of litigation. + References No definition available. + Details
Name: | us-gaap_LitigationSettlementAmountAwardedToOtherParty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- 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_LossContingenciesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Reflects the estimated amount of loss from the specified contingency as of the balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118942415&loc=d3e14435-108349 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 9 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118942415&loc=d3e14557-108349 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=118943654&loc=d3e12021-110248 + Details
Name: | us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | srt_LitigationCaseAxis=cof_AntiMoneyLaunderingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LitigationStatusAxis=us-gaap_PendingLitigationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_LitigationCaseAxis=cof_InterchangeLitigationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_US
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_CA
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |