CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Millions		Total	Citigroup stockholders' equity	Preferred stock at aggregate liquidation value	Total Citigroup common stockholders’ equity	Common stock and additional paid-in capital (APIC)	Retained earnings	Retained earnings Cumulative effect of adoption	[1]	Retained earnings Adjusted balance	Treasury stock, at cost		Citigroup's accumulated other comprehensive income (loss)	Citigroup's accumulated other comprehensive income (loss) Cumulative effect of adoption	[1]	Citigroup's accumulated other comprehensive income (loss) Adjusted balance	Noncontrolling interests
Beginning of year balance, net of tax at Dec. 31, 2020				$ 19,480		$ 107,877	$ 168,272	$ 0		$ 168,272	$ (64,129)		$ (32,058)	$ 0		$ (32,058)	$ 758
Preferred stock, beginning of year (in shares) at Dec. 31, 2020				779,000
Common stock, beginning of year (in shares) at Dec. 31, 2020						3,099,633,000
Treasury stock, beginning of year (in shares) at Dec. 31, 2020											(1,017,544,000)
Increase (Decrease) in Stockholders' Equity
Accounting Standards Update [Extensible Enumeration]		Accounting Standards Update 2016-13 [Member]
Issuance of new preferred stock				$ 3,300
Issuance of new preferred stock (in shares)				132,000
Redemption of preferred stock				$ (3,785)
Redemption of preferred stock (in shares)				(151,000)
Employee benefit plans						$ 85					$ 489	[2]
Employee benefit plans (in shares)						19,000					7,745,000	[2]
Preferred stock issuance costs (new issuances, net of reclassifications to retained earnings for redemptions)						$ 25
Other						47	(40)										(12)
Citigroup’s net income		$ 22,025					21,952										73
Common dividends	[3]						(4,196)
Preferred dividends		(1,040)					(1,040)
Treasury stock acquired	[4]										$ (7,600)
Treasure stock acquired (in shares)	[4]										(105,498,000)
Transactions between Citigroup and the noncontrolling-interest shareholders																	(10)
Distributions paid to noncontrolling-interest shareholders																	(10)
Other comprehensive income (loss)													(6,707)				(99)
Net change in noncontrolling interests																	(58)
End of year balance, net of tax at Dec. 31, 2021		202,672	$ 201,972	$ 18,995	$ 182,977	$ 108,034	184,948	0		184,948	$ (71,240)		(38,765)	0		(38,765)	700
Preferred stock, end of year (in shares) at Dec. 31, 2021				760,000
Common stock, end of year (in shares) at Dec. 31, 2021						3,099,652,000
Treasury stock, end of year (in shares) at Dec. 31, 2021											(1,115,297,000)
Increase (Decrease) in Stockholders' Equity
Total (in shares)					1,984,355,000
Employee benefit plans						$ 455					$ 523	[2]
Employee benefit plans (in shares)						17,000					8,190,000	[2]
Other							1										3
Citigroup’s net income		14,934					14,845										89
Common dividends	[3]						(4,028)
Preferred dividends		(1,032)					(1,032)
Treasury stock acquired	[4]										$ (3,250)
Treasure stock acquired (in shares)	[4]										(55,576,000)
Transactions between Citigroup and the noncontrolling-interest shareholders																	(34)
Distributions paid to noncontrolling-interest shareholders																	(51)
Other comprehensive income (loss)													(8,297)				(58)
Net change in noncontrolling interests																	(51)
End of year balance, net of tax at Dec. 31, 2022		$ 201,838	201,189	$ 18,995	$ 182,194	$ 108,489	194,734	$ 290		$ 195,024	$ (73,967)		(47,062)	$ 27		$ (47,035)	649
Preferred stock, end of year (in shares) at Dec. 31, 2022				760,000
Common stock, end of year (in shares) at Dec. 31, 2022						3,099,669,000
Treasury stock, end of year (in shares) at Dec. 31, 2022		(1,162,682,999)									(1,162,683,000)
Increase (Decrease) in Stockholders' Equity
Total (in shares)					1,936,986,000
Issuance of new preferred stock				$ 2,750
Issuance of new preferred stock (in shares)				110,000
Redemption of preferred stock				$ (4,145)
Redemption of preferred stock (in shares)				(166,000)
Employee benefit plans						$ 452					$ 729	[2]
Employee benefit plans (in shares)						23,000					10,276,000	[2]
Preferred stock issuance costs (new issuances, net of reclassifications to retained earnings for redemptions)						$ 58
Other						(13)	(73)										8
Citigroup’s net income		$ 9,381					9,228										153
Common dividends	[3]						(4,076)
Preferred dividends		(1,198)					(1,198)
Treasury stock acquired	[4]										$ (2,000)
Treasure stock acquired (in shares)	[4]										(44,171,000)
Transactions between Citigroup and the noncontrolling-interest shareholders																	(14)
Distributions paid to noncontrolling-interest shareholders																	(82)
Other comprehensive income (loss)													2,235				84
Net change in noncontrolling interests																	149
End of year balance, net of tax at Dec. 31, 2023		$ 206,251	$ 205,453	$ 17,600	$ 187,853	$ 108,986	$ 198,905				$ (75,238)		$ (44,800)				$ 798
Preferred stock, end of year (in shares) at Dec. 31, 2023				704,000
Common stock, end of year (in shares) at Dec. 31, 2023						3,099,692,000
Treasury stock, end of year (in shares) at Dec. 31, 2023		(1,196,577,865)									(1,196,578,000)
Increase (Decrease) in Stockholders' Equity
Total (in shares)					1,903,114,000

[1] See Note 1 for additional details.

[2] Includes treasury stock related to certain activity under Citi’s employee restricted or deferred stock programs where shares are withheld to satisfy employees’ tax requirements.

[3] Common dividends declared were $0.51 per share for each of 1Q23 and 2Q23, and $0.53 per share for each of 3Q23 and 4Q23; $0.51 per share for each of 1Q22, 2Q22, 3Q22 and 4Q22; and $0.51 per share for each of 1Q21, 2Q21, 3Q21 and 4Q21.

[4] Primarily consists of open market purchases under Citi’s Board of Directors–approved common stock repurchase program.