DEBT - Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument
Weighted average interest rate	3.32%
Long-term debt	$ 201,275	$ 223,080
Weighted average interest rate including effects of derivative contracts	2.55%
Senior debt
Debt Instrument
Long-term debt	$ 172,668	195,868
Subordinated debt
Debt Instrument
Long-term debt	26,894	25,487
Trust preferred securities
Debt Instrument
Long-term debt	1,713	1,725
Citigroup Inc.
Debt Instrument
Long-term debt	$ 142,157
Citigroup Inc. \| Senior debt
Debt Instrument
Weighted average interest rate	3.84%
Long-term debt	$ 113,569	122,323
Citigroup Inc. \| Subordinated debt
Debt Instrument
Weighted average interest rate	4.48%
Long-term debt	$ 26,875	25,464
Citigroup Inc. \| Trust preferred securities
Debt Instrument
Weighted average interest rate	6.90%
Long-term debt	$ 1,713	1,725
Bank
Debt Instrument
Long-term debt	$ 55,131
Bank \| Senior debt
Debt Instrument
Weighted average interest rate	1.58%
Long-term debt	$ 55,131	65,146
Collateralized long-term advances from Federal Home Loan Bank	17,800	19,800
Broker-dealer
Debt Instrument
Long-term debt	$ 3,987
Broker-dealer \| Senior debt
Debt Instrument
Weighted average interest rate	3.25%
Long-term debt	$ 3,968	8,399
Broker-dealer \| Subordinated debt
Debt Instrument
Weighted average interest rate	1.18%
Long-term debt	$ 19	$ 23

Represents the weighted average interest rate at the end of the period after the effect of the derivative contract.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Including both current and noncurrent portions, Federal Home Loan Bank borrowings initially due beyond one year or beyond the normal operating cycle if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64702-112823

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822

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- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 20, 22
-Article 5

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- Definition

Weighted average interest rate of long-term debt outstanding.

+ References

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