RETIREMENT BENEFITS (Details 5) (USD $)	3 Months Ended	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Defined Contribution Pension and Other Postretirement Plans Disclosure
Maximum percentage contribution by employer of employees eligible pay			6.00%	6.00%
Maximum compensation to be eligible for fixed contribution from employer			$ 100,000
Percentage of fixed contribution by employer, for eligible employees whose compensation is $100,000 or less			2.00%
Pretax expense associated with Citigroup 401(k) plan	98,000,000	92,000,000	202,000,000	196,000,000
Postemployment Plans
Net Expense
Benefits earned during the period	6,000,000	6,000,000	13,000,000	12,000,000
Interest cost on benefit obligation	3,000,000	3,000,000	6,000,000	7,000,000
Amortization of unrecognized
Prior service cost (benefit)	2,000,000	2,000,000	4,000,000	4,000,000
Net actuarial loss	3,000,000	3,000,000	6,000,000	6,000,000
Total service related expense	14,000,000	14,000,000	29,000,000	29,000,000
Non-service related expense	6,000,000	6,000,000	13,000,000	12,000,000
Total net (benefit) expense	$ 20,000,000	$ 20,000,000	$ 42,000,000	$ 41,000,000

Represents the non-service related expense for defined benefit plans for the period.

No definition available.

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Represents the service related expense for defined benefit plans for the period.

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Represents the maximum compensations of employees to be eligible to receive the fixed contributions from employer.

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No definition available.

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The percentage of matching contribution made by the employer to a defined contribution plan for participating employees during the period.

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Represents the percentage of fixed contribution for eligible employees whose compensation is 100,000 or less.

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Amount of gain (loss) from a decision to temporarily deviate from the substantive plan, or from a change in benefit obligation or plan asset value from changes in actuarial assumptions, for example, but not limited to, interest, mortality, employee turnover or salary scale.

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The amount of the prior service cost or credit recognized in net periodic benefit cost relating to benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation.

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- Definition

The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

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The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments.

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The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

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The amount of the cost recognized during the period for defined contribution plans.

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