Financing Receivables - Past Due (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Past Due Financing Receivable
Amortized Cost	$ 11,957.0	$ 13,640.0
Client Financing Receivables
Past Due Financing Receivable
Amortized Cost	11,349.0	12,397.0
Amortized Cost Not Accruing	186.0	205.0
Impaired financing receivables, related allowance	135.0	153.0
Client Financing Receivables \| Total Past Due > 90 days
Past Due Financing Receivable
Amortized Cost	498.0	312.0
Amortized Cost > 90 Days and Accruing	315.0	112.0
Billed Invoices > 90 Days and Accruing	12.0	10.0
Client Financing Receivables \| Americas
Past Due Financing Receivable
Amortized Cost	6,116.0	6,573.0
Amortized Cost Not Accruing	77.0	90.0
Client Financing Receivables \| Americas \| Total Past Due > 90 days
Past Due Financing Receivable
Amortized Cost	356.0	188.0
Amortized Cost > 90 Days and Accruing	282.0	100.0
Billed Invoices > 90 Days and Accruing	8.0	6.0
Client Financing Receivables \| EMEA
Past Due Financing Receivable
Amortized Cost	3,333.0	3,793.0
Amortized Cost Not Accruing	90.0	95.0
Client Financing Receivables \| EMEA \| Total Past Due > 90 days
Past Due Financing Receivable
Amortized Cost	97.0	99.0
Amortized Cost > 90 Days and Accruing	7.0	7.0
Billed Invoices > 90 Days and Accruing	2.0	2.0
Client Financing Receivables \| Asia Pacific
Past Due Financing Receivable
Amortized Cost	1,900.0	2,031.0
Amortized Cost Not Accruing	19.0	20.0
Client Financing Receivables \| Asia Pacific \| Total Past Due > 90 days
Past Due Financing Receivable
Amortized Cost	45.0	25.0
Amortized Cost > 90 Days and Accruing	26.0	5.0
Billed Invoices > 90 Days and Accruing	$ 2.0	$ 2.0

Billed invoices in financing receivables that are 90 days or more past due and still accruing.

No definition available.

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Namespace Prefix:	ibm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of financing receivable 90 days or more past due and still accruing.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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+ Details

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- Definition

Amount of financing receivable on nonaccrual status.

+ References

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-Publisher FASB
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-Publisher SEC
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- 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

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- Definition

Amount of allowance for credit losses related to recorded investment.

+ References

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-Publisher FASB
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+ Details

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- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

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+ Details

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- Details

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