DEBT - Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument
Weighted average interest rate	3.28%
Long-term debt	$ 248,760	$ 231,999
Weighted average interest rate after effect of derivative contract	3.54%
Senior debt
Debt Instrument
Long-term debt	$ 221,449	205,695
Subordinated debt
Debt Instrument
Long-term debt	25,589	24,593
Trust preferred securities
Debt Instrument
Long-term debt	1,722	1,711
Citigroup Inc.
Debt Instrument
Long-term debt	$ 150,477
Citigroup Inc. \| Senior debt
Debt Instrument
Weighted average interest rate	3.11%
Long-term debt	$ 123,292	117,511
Citigroup Inc. \| Subordinated debt
Debt Instrument
Weighted average interest rate	5.59%
Long-term debt	$ 25,463	24,545
Citigroup Inc. \| Trust preferred securities
Debt Instrument
Weighted average interest rate	8.15%
Long-term debt	$ 1,722	1,711
Bank
Debt Instrument
Long-term debt	$ 53,340
Bank \| Senior debt
Debt Instrument
Weighted average interest rate	2.51%
Long-term debt	$ 53,340	61,237
Collateralized long-term advances from Federal Home Loan Bank	5,500	10,500
Broker-dealer
Debt Instrument
Long-term debt	$ 44,943
Broker-dealer \| Senior debt
Debt Instrument
Weighted average interest rate	2.43%
Long-term debt	$ 44,817	26,947
Broker-dealer \| Subordinated debt
Debt Instrument
Weighted average interest rate	2.37%
Long-term debt	$ 126	$ 48

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

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- Definition

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+ References

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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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. 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/disclosureRef
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Weighted average interest rate of long-term debt outstanding calculated at point in time.

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