GOODWILL AND INTANGIBLE ASSETS - Changes in Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Finite and Indefinite-lived Intangible Assets
Beginning balance	$ 3,734
Acquisitions/ renewals/ divestitures	3
Amortization	(245)
Impairments	0
FX translation and other	33
Ending balance	3,525
Mortgage servicing rights (MSRs)	759	$ 760
Total intangible assets	4,284	$ 4,494
Purchased credit card relationships
Finite and Indefinite-lived Intangible Assets
Beginning balance	808
Acquisitions/ renewals/ divestitures	0
Amortization	(132)
Impairments	0
FX translation and other	0
Ending balance	676
Credit card contract related intangibles
Finite and Indefinite-lived Intangible Assets
Beginning balance	2,681
Acquisitions/ renewals/ divestitures	1
Amortization	(92)
Impairments	0
FX translation and other	2
Ending balance	2,592
Other customer relationships
Finite and Indefinite-lived Intangible Assets
Beginning balance	47
Acquisitions/ renewals/ divestitures	2
Amortization	(20)
Impairments	0
FX translation and other	1
Ending balance	30
Present value of future profits
Finite and Indefinite-lived Intangible Assets
Beginning balance	1
Acquisitions/ renewals/ divestitures	0
Amortization	(1)
Impairments	0
FX translation and other	0
Ending balance	0
Indefinite-lived intangible assets
Finite and Indefinite-lived Intangible Assets
Beginning balance	197
Acquisitions/ renewals/ divestitures	0
Amortization	0
Impairments	0
FX translation and other	30
Ending balance	$ 227

No definition available.

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- Definition

Sum of the carrying amounts of all intangible assets, excluding goodwill and excluding mortgage servicing rights, as of the balance sheet date, net of accumulated amortization and impairment charges.

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

Intangible Assets, Excluding Mortgage Servicing Rights Acquisitions (Divestitures)

+ References

No definition available.

+ Details

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Balance Type:	debit
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- Definition

This element represents the aggregate amount of amortization of intangible assets excluding mortgage servicing rights (MSRs) during the period.

+ References

No definition available.

+ Details

Name:	c_IntangibleAssetsExcludingMortgageServicingRightsAmortizationOfIntangibleAssets
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Balance Type:	debit
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- Definition

This element represents the aggregate amount of impairment of intangible assets excluding mortgage servicing rights (MSRs) during the period.

+ References

No definition available.

+ Details

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Balance Type:	debit
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- Definition

This element represents net changes to the recorded value of intangible assets excluding mortgage servicing rights (MSRs), due to foreign currency translation adjustments and purchase accounting adjustments.

+ References

No definition available.

+ Details

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Namespace Prefix:	c_
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- Definition

This element represents the sum of the carrying amounts of all intangible assets excluding goodwill but including mortgage servicing rights, as of the balance sheet date that is net of accumulated amortization and impairment charges.

+ References

No definition available.

+ Details

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Namespace Prefix:	c_
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Balance Type:	debit
Period Type:	instant

- Definition

The amount of mortgage servicing rights (MSRs) as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	c_MortgageServicingRightsMSR
Namespace Prefix:	c_
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Period Type:	instant

- Details

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- Details

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- Details

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- Details

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