INVESTMENTS (Details 10) (USD $)	3 Months Ended
Mar. 31, 2012 D
Investments in Alternative Investment Funds
Alternative investment funds, fair value	$ 2,417,000,000
Alternative investment funds, unfunded commitments	589,000,000
Amount of fund assets valued using net asset values provided by third party asset managers which is included in the total fair value amount of alternative investment funds	500,000,000
Hedge funds
Investments in Alternative Investment Funds
Alternative investment funds, fair value	1,244,000,000
Alternative investment funds, redemption frequency (if currently eligible)	Generally quarterly
Alternative investment funds, maximum redemption notice period (in days)	95
Alternative investment funds, minimum redemption notice period (in days)	10
Private equity funds
Investments in Alternative Investment Funds
Alternative investment funds, fair value	957,000,000
Alternative investment funds, unfunded commitments	431,000,000
Alternative investment funds, carried at cost	7,000,000
Real estate funds
Investments in Alternative Investment Funds
Alternative investment funds, fair value	216,000,000
Alternative investment funds, unfunded commitments	$ 158,000,000

Represents the carrying value of funds that carry at cost.

No definition available.

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- Definition

The redemption frequency of alternative investment funds that calculate net asset value per share.

+ References

No definition available.

+ Details

Name:	c_AlternativeInvestmentFundsRedemptionFrequency
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- Definition

Represents the maximum redemption notice period of alternative investment funds.

+ References

No definition available.

+ Details

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Namespace Prefix:	c_
Data Type:	xbrli:integerItemType
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- Definition

Represents the minimum redemption notice period of alternative investment funds.

+ References

No definition available.

+ Details

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- Definition

The amount of fund assets that are valued using NAV (net asset value) provided by third party asset managers is included in total alternative investment fund fair value.

+ References

No definition available.

+ Details

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

- Definition

This element represents the total fair market value of investments in certain entities that calculate net asset value per share (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments). This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements, but may also be used in both the balance sheet and disclosure in the same submission. This item represents alternative investments as of the balance sheet date which may include investments in certain hedge funds, venture capital funds, private equity funds, real estate partnerships or funds, and any other investment in which investee management calculates net asset value per share as the primary metric for investment value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph a

-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 5

-Subparagraph a

-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19296-110258

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Subparagraph (a)

-Paragraph 6A

-URI http://asc.fasb.org/extlink&oid=6925170&loc=SL6742756-110258

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

The amount of unfunded commitments for which the entity is obligated, to those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 6A

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6925170&loc=SL6742756-110258

+ Details

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Balance Type:	credit
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- Details

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