EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended
		Mar. 31, 2025	Mar. 31, 2024
Antidilutive Securities Excluded from Computation of Earnings Per Share
Income from continuing operations before attribution of noncontrolling interests		$ 4,108	$ 3,408
Noncontrolling interests		43	36
Net income from continuing operations (for EPS purposes)		4,065	3,372
Income (loss) from discontinued operations, net of taxes		(1)	(1)
Citigroup’s net income		4,064	3,371
Less: Preferred dividends		269	279
Net income available to common shareholders		3,795	3,092
Less: Dividends and undistributed earnings allocated to employee restricted and deferred shares with rights to dividends, and other relevant items, applicable to basic EPS		44	45
Net income allocated to common shareholders for basic EPS		$ 3,751	$ 3,047
Weighted-average common shares outstanding applicable to basic EPS (in shares)		1,879.0	1,910.4
Basic earnings per share
Income from continuing operations (in dollars per share)	[1]	$ 2.00	$ 1.60
Discontinued operations (in dollars per share)	[1]	0	0
Net income (in dollars per share)	[1]	$ 2.00	$ 1.59
Add back: Dividends allocated to employee restricted and deferred shares with rights to dividends that are forfeitable		$ 17	$ 15
Net income allocated to common shareholders for diluted EPS		$ 3,768	$ 3,062
Effect of dilutive securities
Other employee plans (in shares)		40.6	32.8
Adjusted weighted-average common shares outstanding applicable to diluted EPS (in shares)		1,919.6	1,943.2
Diluted earnings per share
Income from continuing operations (in dollars per share)	[1]	$ 1.96	$ 1.58
Discontinued operations (in dollars per share)	[1]	0	0
Net income (in dollars per share)	[1]	$ 1.96	$ 1.58
Income allocated to employees with no rights to dividends		$ 40
Series V
Diluted earnings per share
Issuance costs		$ 4

[1] Due to rounding, earnings per share on continuing operations and discontinued operations may not sum to earnings per share on net income.