BASIS OF PRESENTATION (Details)	6 Months Ended
Jun. 30, 2011
BASIS OF PRESENTATION
Number of significant accounting policies	6
Minimum voting rights percentage for consolidation (as a percent)	50.00%
Equity method investment ownership, low end (as a percent)	20.00%
Equity method investment ownership, high end (as a percent)	50.00%
Ownership percentage, if less than this amount then income from investments is recognized when dividends are received (as a percent)	20.00%

- Details

Name:	c_BasisOfPresentationDisclosureAbstract
Namespace Prefix:	c
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the high end of range of percentage of ownership of common stock or equity participation in the investee, accounted for under the equity method of accounting.

+ Details

Name:	c_EquityMethodInvestmentOwnershipPercentageHighEnd
Namespace Prefix:	c
Data Type:	us-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the low end of range of percentage of ownership of common stock or equity participation in the investee, accounted for under the equity method of accounting.

+ Details

Name:	c_EquityMethodInvestmentOwnershipPercentageLowEnd
Namespace Prefix:	c
Data Type:	us-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The maximum percentage of ownership for the entity to reflect recognition of income as dividends is received.

+ Details

Name:	c_MaximumOwnershipPercentageIncomeRecognitionUponReceiptOfDividends
Namespace Prefix:	c
Data Type:	us-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of significant accounting policies identified by the entity.

+ Details

Name:	c_NumberOfSignificantAccountingPolicies
Namespace Prefix:	c
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The minimum voting rights percentage owned by the entity that triggers consolidation.

+ Details

Name:	c_VotingRightsPercentageTriggerConsolidation
Namespace Prefix:	c
Data Type:	us-types:percentItemType
Balance Type:	na
Period Type:	duration