SECURITIZATIONS AND VARIABLE INTEREST ENTITIES (Details 2) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	$ 22,098	$ 24,911
Citicorp
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	21,559	23,998
Citicorp | Citi-administered asset-backed commercial paper conduits (ABCP) | Liquidity Facilities Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	11,529
Citicorp | Third-party commercial paper conduits | Liquidity Facilities Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	298
Citicorp | Asset-based financing | Liquidity Facilities Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	5
Citicorp | Asset-based financing | Loan Commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	2,979
Citicorp | Municipal securities tender option bond trusts (TOBs) | Liquidity Facilities Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	5,356
Citicorp | Municipal investments | Liquidity Facilities Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	344
Citicorp | Municipal investments | Loan Commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	879
Citicorp | Investment funds | Loan Commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	57
Citicorp | Other. | Loan Commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	112
Citicorp | Liquidity Facilities Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	17,532
Citicorp | Loan Commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	4,027
Citi Holdings
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	539	913
Citi Holdings | Collateralized loan obligations (CLOs) | Loan Commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	7
Citi Holdings | Asset-based financing | Liquidity Facilities Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	70
Citi Holdings | Asset-based financing | Loan Commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	217
Citi Holdings | Municipal investments | Loan Commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	85
Citi Holdings | Other. | Loan Commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	160
Citi Holdings | Liquidity Facilities Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	70
Citi Holdings | Loan Commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	469
Liquidity Facilities Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	17,602
Loan Commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	$ 4,496