SUBSEQUENT EVENT	12 Months Ended
Dec. 31, 2020
Subsequent Events [Abstract]
SUBSEQUENT EVENT	SUBSEQUENT EVENTAs a result of new information Citi received subsequent to December 31, 2020, Citi adjusted downward its 2020 financial results (recognized in the fourth quarter of 2020) from those previously reported on January 15, 2021, due to a $390 million increase in operating expenses ($323 million after-tax) recorded within ICG, resulting from operational losses related to certain legal matters. Citi’s results of operations and financial condition for the full year 2020, as reported in this Annual Report on Form 10‐K for the year ended December 31, 2020, reflect the impact of this adjustment.

The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-URI http://asc.fasb.org/topic&trid=2122774

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6842918&loc=SL6314017-165662

Name:	us-gaap_SubsequentEventsTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration