SECURITIZATIONS AND VARIABLE INTEREST ENTITIES - Funding, Liquidity Facilities and Subordinated Interests (Details) - USD ($) $ in Billions	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Citibank Credit Card Master Trust (Master Trust)
Funding, Liquidity Facilities and Subordinated Interests
Weighted average maturity of term notes	3 years 3 months 18 days	3 years 7 months 6 days
Term notes issued to third parties	$ 8.4	$ 8.4
Term notes retained by Citigroup affiliates	1.7	2.2
Total Trust liabilities	$ 10.1	$ 10.6
Citibank OMNI Master Trust (Omni Trust)
Funding, Liquidity Facilities and Subordinated Interests
Weighted average maturity of term notes	1 year 4 months 24 days	1 year 7 months 6 days
Term notes issued to third parties	$ 1.3	$ 1.3
Term notes retained by Citigroup affiliates	4.8	5.0
Total Trust liabilities	$ 6.1	$ 6.3