SECURITIZATIONS AND VARIABLE INTEREST ENTITIES (Details 4) (USD $)	9 Months Ended			3 Months Ended		9 Months Ended			3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014 Citicorp	Dec. 31, 2013 Citicorp	Sep. 30, 2014 Citicorp Credit card securitizations	Sep. 30, 2013 Citicorp Credit card securitizations	Sep. 30, 2014 Citicorp Credit card securitizations	Sep. 30, 2013 Citicorp Credit card securitizations	Dec. 31, 2013 Citi Holdings	Sep. 30, 2013 Citi Holdings Credit card securitizations	Sep. 30, 2014 Citi Holdings Credit card securitizations	Sep. 30, 2013 Citi Holdings Credit card securitizations
Securitized credit card receivables
Gains (losses) recognized on the securitization	$ 0
Ownership interests in principal amount of trust credit card receivables
Sold to investors via trust-issued securities		37,900,000,000	32,300,000,000
Retained by Citigroup as trust-issued securities		10,000,000,000	8,100,000,000					1,300,000,000
Retained by Citigroup via non-certificated interests		11,600,000,000	12,100,000,000
Total ownership interests in principal amount of trust credit card receivables		59,500,000,000	52,500,000,000					1,300,000,000
Cash Flows Between Transferor and Transferee
Proceeds from new securitizations				3,100,000,000	4,900,000,000	9,800,000,000	7,400,000,000		200,000,000	100,000,000	200,000,000
Pay down of maturing notes				$ (2,800,000,000)		$ (4,100,000,000)	$ (1,600,000,000)				$ (100,000,000)