LOANS (Details 3) (USD $)	12 Months Ended		12 Months Ended			3 Months Ended	12 Months Ended		3 Months Ended	12 Months Ended		3 Months Ended	12 Months Ended
	Dec. 31, 2013 Q	Dec. 31, 2012 Q	Dec. 31, 2013 Consumer	Dec. 31, 2012 Consumer	Dec. 31, 2011 Consumer	Sep. 30, 2012 Consumer New OCC guidance	Dec. 31, 2013 Consumer Residential First Mortgage Loans	Dec. 31, 2012 Consumer Residential First Mortgage Loans	Sep. 30, 2012 Consumer Residential First Mortgage Loans New OCC guidance	Dec. 31, 2013 Consumer Home equity loans	Dec. 31, 2012 Consumer Home equity loans	Sep. 30, 2012 Consumer Home equity loans New OCC guidance	Dec. 31, 2013 Consumer Credit cards	Dec. 31, 2012 Consumer Credit cards	Dec. 31, 2013 Consumer Individual installment and other	Dec. 31, 2012 Consumer Individual installment and other	Dec. 31, 2013 Consumer Commercial market loans	Dec. 31, 2012 Consumer Commercial market loans
LOANS
Maximum period of loan modification under Citi's short-term modification programs	12 months
Number of quarters used to calculate the average recorded investment balance	4	4
Financing receivable impaired
Recorded investment in receivables reclassified to TDR as a result of new guidance issued by OCC						$ 1,714,000,000			$ 1,327,000,000			$ 387,000,000
Recorded investment			23,793,000,000	29,640,000,000			16,801,000,000	20,870,000,000		2,141,000,000	2,135,000,000		3,339,000,000	4,584,000,000	1,114,000,000	1,612,000,000	398,000,000	439,000,000
Unpaid principal balance			25,727,000,000	31,783,000,000			17,788,000,000	22,062,000,000		2,806,000,000	2,727,000,000		3,385,000,000	4,639,000,000	1,143,000,000	1,618,000,000	605,000,000	737,000,000
Related specific allowance			4,633,000,000	6,941,000,000			2,309,000,000	3,585,000,000		427,000,000	636,000,000		1,178,000,000	1,800,000,000	536,000,000	860,000,000	183,000,000	60,000,000
Average carrying value			24,950,000,000	29,592,000,000			17,616,000,000	19,956,000,000		2,116,000,000	1,911,000,000		3,720,000,000	5,272,000,000	1,094,000,000	1,958,000,000	404,000,000	495,000,000
Interest income recognized			1,280,000,000	1,520,000,000	1,711,000,000		790,000,000	875,000,000		81,000,000	68,000,000		234,000,000	308,000,000	153,000,000	248,000,000	22,000,000	21,000,000
Impaired financing receivable without specific allowance							2,169,000,000	2,344,000,000		568,000,000	378,000,000						111,000,000	183,000,000
Smaller-balance impaired consumer loans modified since January 1, 2008, dollar amount			23,400,000,000	29,200,000,000
Amounts of such outstanding modified consumer loans, including those modified prior to 2008			$ 24,000,000,000	$ 30,100,000,000