SUBSIDIARY GUARANTEES - Summarized Income Statement (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2025	Mar. 31, 2024
Condensed Income Statements
Total revenues, net of interest expense	[1]	$ 21,596	$ 21,016
Total operating expenses	[1]	13,425	14,107
Provision for credit losses	[1]	2,723	2,365
Income from continuing operations before income taxes		5,448	4,544
Provision (benefits) for income taxes		1,340	1,136
Citigroup’s net income		4,064	$ 3,371
Citigroup Inc. | Reportable legal entities
Condensed Income Statements
Total revenues, net of interest expense		352
Total operating expenses		66
Provision for credit losses		0
Equity in undistributed income of subsidiaries		3,061
Income from continuing operations before income taxes		3,347
Provision (benefits) for income taxes		(717)
Citigroup’s net income		4,064
CGMHI | Reportable legal entities
Condensed Income Statements
Total revenues, net of interest expense		3,330
Total operating expenses		4,987
Provision for credit losses		28
Equity in undistributed income of subsidiaries		0
Income from continuing operations before income taxes		(1,685)
Provision (benefits) for income taxes		22
Citigroup’s net income		$ (1,707)

[1]     Effective January 1, 2025, certain transaction processing fees paid by Citi, primarily to credit card networks, which were previously presented within Other operating expenses, are presented as contra-revenue within Commissions and fees reported in Non-interest revenue. Prior periods were conformed to reflect this change in presentation.