SECURITIZATIONS AND VARIABLE INTEREST ENTITIES (Details 2) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	$ 18,520	$ 24,866
Liquidity facilities Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	12,697
Loan commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	5,823
Citicorp
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	17,190	23,546
Citicorp | Liquidity facilities Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	12,697
Citicorp | Liquidity facilities Citigroup | Citi-administered asset-backed commercial paper conduits (ABCP)
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	7,906
Citicorp | Liquidity facilities Citigroup | Asset-based financing
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	6
Citicorp | Liquidity facilities Citigroup | Municipal securities tender option bond trusts (TOBs)
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	4,785
Citicorp | Loan commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	4,493
Citicorp | Loan commitments Citigroup | Asset-based financing
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	2,877
Citicorp | Loan commitments Citigroup | Municipal investments
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	1,454
Citicorp | Loan commitments Citigroup | Other
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	162
Citi Holdings
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	1,330	1,320
Citi Holdings | Loan commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	1,330
Citi Holdings | Loan commitments Citigroup | Asset-based financing
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	328
Citi Holdings | Loan commitments Citigroup | Municipal investments
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	$ 1,002