SECURITIZATIONS AND VARIABLE INTEREST ENTITIES - Carrying Amounts and Classifications of Consolidated Assets (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Variable Interest Entity
Cash	$ 32,108,000,000us-gaap_CashAndDueFromBanks	$ 29,885,000,000us-gaap_CashAndDueFromBanks	$ 36,453,000,000us-gaap_CashAndDueFromBanks	$ 28,701,000,000us-gaap_CashAndDueFromBanks
Trading account assets	296,786,000,000us-gaap_TradingSecurities	285,928,000,000us-gaap_TradingSecurities
Investments	333,443,000,000c_InvestmentsExcludingTradingSecurities	308,980,000,000c_InvestmentsExcludingTradingSecurities
Total loans, net	628,641,000,000	645,824,000,000
Other assets	122,122,000,000us-gaap_OtherAssets	124,919,000,000us-gaap_OtherAssets
Total assets	1,842,181,000,000us-gaap_Assets	1,880,035,000,000us-gaap_Assets
Consolidated VIEs
Variable Interest Entity
Cash	300,000,000	400,000,000
Trading account assets	700,000,000	1,000,000,000
Investments	8,000,000,000	10,900,000,000
Total loans, net	93,100,000,000	91,900,000,000
Other assets	600,000,000	1,300,000,000
Total assets	102,700,000,000	105,500,000,000
Short-term borrowings	22,700,000,000	24,300,000,000
Long-term debt	40,100,000,000	34,800,000,000
Other liabilities	900,000,000	1,000,000,000
Total Liabilities	63,700,000,000	60,100,000,000
Significant unconsolidated VIE assets
Variable Interest Entity
Trading account assets	7,600,000,000	5,400,000,000
Investments	2,600,000,000	4,100,000,000
Total loans, net	25,000,000,000	18,800,000,000
Other assets	2,000,000,000	2,700,000,000
Total assets	37,200,000,000	31,000,000,000
Citicorp \| Consolidated VIEs
Variable Interest Entity
Cash	100,000,000	200,000,000
Trading account assets	700,000,000	1,000,000,000
Investments	8,000,000,000	10,900,000,000
Total loans, net	90,600,000,000	83,200,000,000
Other assets	600,000,000	1,100,000,000
Total assets	100,000,000,000	96,400,000,000
Short-term borrowings	22,700,000,000	24,300,000,000
Long-term debt	38,100,000,000	32,800,000,000
Other liabilities	800,000,000	900,000,000
Total Liabilities	61,600,000,000	58,000,000,000
Citicorp \| Significant unconsolidated VIE assets
Variable Interest Entity
Trading account assets	7,400,000,000	4,800,000,000
Investments	2,400,000,000	3,700,000,000
Total loans, net	24,900,000,000	18,200,000,000
Other assets	1,800,000,000	2,200,000,000
Total assets	36,500,000,000	28,900,000,000
Citi Holdings \| Consolidated VIEs
Variable Interest Entity
Cash	200,000,000	200,000,000
Trading account assets	0	0
Investments	0	0
Total loans, net	2,500,000,000	8,700,000,000
Other assets	0	200,000,000
Total assets	2,700,000,000	9,100,000,000
Short-term borrowings	0	0
Long-term debt	2,000,000,000	2,000,000,000
Other liabilities	100,000,000	100,000,000
Total Liabilities	2,100,000,000	2,100,000,000
Citi Holdings \| Significant unconsolidated VIE assets
Variable Interest Entity
Trading account assets	200,000,000	600,000,000
Investments	200,000,000	400,000,000
Total loans, net	100,000,000	600,000,000
Other assets	200,000,000	500,000,000
Total assets	$ 700,000,000	$ 2,100,000,000

Sum of the carrying amounts as of the balance sheet date of all investments, excluding trading account assets.

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Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Also includes long term debt that the creditor have recourse to the general credit of the reporting entity.

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Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer including short term debt that the creditor have recourse to the general credit of the reporting entity.

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Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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For banks and other depository institutions: Includes cash on hand (currency and coin), cash items in process of collection, noninterest bearing deposits due from other financial institutions (including corporate credit unions), and noninterest bearing balances with the Federal Reserve Banks, Federal Home Loan Banks and central banks.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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The aggregate carrying amounts, as of the balance sheet date, of assets not separately disclosed in the balance sheet.

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Amount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

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The carrying amount of the consolidated Variable Interest Entity's liabilities included in the reporting entity's statement of financial position.

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