SECURITIZATIONS AND VARIABLE INTEREST ENTITIES (Details 2) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	$ 19,306	$ 24,866
Liquidity facilities Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	13,533
Loan commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	5,773
Citicorp
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	17,989	23,546
Citicorp | Liquidity facilities Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	13,454
Citicorp | Liquidity facilities Citigroup | Citi-administered asset-backed commercial paper conduits (ABCP)
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	8,631
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	4,817
Citicorp | Loan commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	4,535
Citicorp | Loan commitments Citigroup | Asset-based financing
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	2,733
Citicorp | Loan commitments Citigroup | Municipal investments
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	1,470
Citicorp | Loan commitments Citigroup | Investment funds
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	43
Citicorp | Loan commitments Citigroup | Other
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	289
Citi Holdings
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	1,317	1,320
Citi Holdings | Liquidity facilities Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	79
Citi Holdings | Liquidity facilities Citigroup | Asset-based financing
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	79
Citi Holdings | Loan commitments Citigroup
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	1,238
Citi Holdings | Loan commitments Citigroup | Collateralized loan obligations (CLOs)
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	6
Citi Holdings | Loan commitments Citigroup | Asset-based financing
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	200
Citi Holdings | Loan commitments Citigroup | Municipal investments
Funding Commitments for Significant Unconsolidated VIEs
Notional amount	$ 1,032