Fee income earned from related parties related to financing incentives to a third party.

No definition available.

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Namespace Prefix:	ibmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The change from year to year in the fee income earned from related parties.

+ References

No definition available.

+ Details

Name:	ibmc_RelatedPartyInformationFeeIncomeChange
Namespace Prefix:	ibmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The increase (decrease) in finance income earned from a related party over the prior year.

+ References

No definition available.

+ Details

Name:	ibmc_RelatedPartyInformationFinancialServicesRevenueChange
Namespace Prefix:	ibmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The increase (decrease) in interest income earned from a related party over the prior year.

+ References

No definition available.

+ Details

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Namespace Prefix:	ibmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of revenue earned from financing of related party trade receivables.

+ References

No definition available.

+ Details

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Namespace Prefix:	ibmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

For an unclassified balance sheet, amount of receivables due from an entity that is affiliated with the reporting entity by means of direct or indirect ownership.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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+ Details

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

- Definition

Amount of interest income earned from interest-bearing assets owed to the entity by related party.

+ References

No definition available.

+ Details

Name:	us-gaap_InterestIncomeRelatedParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

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Name:	us-gaap_IncomeStatementLocationAxis=ibmc_FinancialServicesRevenueMember
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Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=ibmc_LoansAndLeasesReceivableFromRelatedPartyMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=ibmc_LongTermParticipatedReceivablesFromRelatedPartyMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=ibmc_ShortTermPurchasedReceivablesFromRelatedPartyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=ibmc_InternationalBusinessMachinesMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=ibmc_ExcessCashInShortTermInterestBearingAccountsWithParentMember
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Relationship with IBM and Related Party Transactions - Operating Relationship (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Disclosures
Other receivables from IBM	$ 792		$ 792		$ 513
Financing revenue
Disclosures
Fee income from related party related to financing incentives to third party	24		65
Change in fee income	(9)		(17)
Financing receivables from IBM
Disclosures
Net financing receivables	3,735		3,735		3,870
Long-term participated receivables from IBM
Disclosures
Net financing receivables	4,312		4,312		4,303
Short-term purchased receivables from IBM
Disclosures
Net financing receivables	50		50		56
IBM
Disclosures
Other receivables from IBM	792		792		513
IBM \| Excess cash in short-term interest-bearing accounts with parent
Disclosures
Other receivables from IBM	781		781		$ 509
IBM \| Financing revenue \| Excess cash in short-term interest-bearing accounts with parent
Disclosures
Interest income from a related party	1	$ 7	2	$ 15
IBM \| Financing receivables from IBM \| Financing revenue
Disclosures
Interest income from a related party	26		60
Increase (decrease) in interest income over the prior year	(19)		(29)
IBM \| Long-term participated receivables from IBM \| Financing revenue
Disclosures
Interest income from a related party	54		105
Increase (decrease) in financial services revenue over the prior year	7		8
IBM \| Short-term purchased receivables from IBM \| Financing revenue
Disclosures
Financing revenue	2		6
Increase (decrease) in financial services revenue over the prior year	$ (6)		$ (17)