SECURITIZATIONS AND VARIABLE INTEREST ENTITIES (Details 2) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	$ 20,989	$ 23,741
Liquidity facilities Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	15,586
Loan commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	5,403
Citicorp
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	20,678	23,399
Citicorp | Liquidity facilities Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	15,505
Citicorp | Liquidity facilities Citigroup | Citi-administered asset-backed commercial paper conduits (ABCP)
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	10,481
Citicorp | Liquidity facilities Citigroup | Asset-based financing
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	5
Citicorp | Liquidity facilities Citigroup | Municipal securities tender option bond trusts (TOBs)
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	5,019
Citicorp | Loan commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	5,173
Citicorp | Loan commitments Citigroup | Asset-based financing
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	3,577
Citicorp | Loan commitments Citigroup | Municipal investments
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	1,330
Citicorp | Loan commitments Citigroup | Investment funds
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	48
Citicorp | Loan commitments Citigroup | Other
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	218
Citi Holdings
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	311	342
Citi Holdings | Liquidity facilities Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	81
Citi Holdings | Liquidity facilities Citigroup | Asset-based financing
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	81
Citi Holdings | Loan commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	230
Citi Holdings | Loan commitments Citigroup | Collateralized loan obligations (CLOs)
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	9
Citi Holdings | Loan commitments Citigroup | Asset-based financing
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	156
Citi Holdings | Loan commitments Citigroup | Municipal investments
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	$ 65