CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Millions		Total	Citigroup stockholders' equity	Preferred stock at aggregate liquidation value	Citigroup common stockholders' equity	Common stock and additional paid-in capital	Retained earnings		Treasury stock, at cost		Citigroup's accumulated other comprehensive income (loss)	Noncontrolling interests
Balance, beginning of period at Dec. 31, 2015				$ 16,718		$ 108,319	$ 133,841		$ (7,677)		$ (29,344)	$ 1,235
Adjustment to opening balance, net of taxes at Dec. 31, 2015	[1]						15				(15)
Adjusted balance, beginning of period at Dec. 31, 2015							133,856				(29,359)
Increase (Decrease) in Stockholders' Equity
Issuance of new preferred stock				2,535
Employee benefit plans						(371)			775	[2]
Treasury stock acquired	[3]								(5,167)
Preferred stock issuance expense						(37)
Other						(5)	0	[4]				(33)
Citigroup’s net income		$ 11,387					11,339					48
Common dividends	[5]						(760)
Preferred dividends		(757)					(757)
Transactions between noncontrolling-interest shareholders and the related consolidated subsidiary												(11)
Transactions between Citigroup and the noncontrolling-interest shareholders												(69)
Dividends paid to noncontrolling-interest shareholders												(42)
Other comprehensive income (loss)											2,166	(13)
Net change in noncontrolling interests												(120)
Balance, end of period at Sep. 30, 2016		232,690	$ 231,575	19,253	$ 212,322	107,906	143,678		(12,069)		(27,193)	1,115
Balance, beginning of period at Jun. 30, 2016											(26,115)
Increase (Decrease) in Stockholders' Equity
Citigroup’s net income		3,857
Preferred dividends		(225)
Other comprehensive income (loss)											(1,078)
Balance, end of period at Sep. 30, 2016		232,690	231,575	19,253	212,322	107,906	143,678		(12,069)		(27,193)	1,115
Balance, beginning of period at Dec. 31, 2016		226,143		19,253		108,073	146,477		(16,302)		(32,381)	1,023
Adjustment to opening balance, net of taxes at Dec. 31, 2016	[1]						(660)				504
Adjusted balance, beginning of period at Dec. 31, 2016							145,817				(31,877)
Increase (Decrease) in Stockholders' Equity
Issuance of new preferred stock				0
Employee benefit plans						(137)			526	[2]
Treasury stock acquired	[3]								(9,053)
Preferred stock issuance expense						0
Other						(9)	(90)	[4]				(61)
Citigroup’s net income		12,136					12,095					41
Common dividends	[5]						(1,755)
Preferred dividends		(893)					(893)
Transactions between noncontrolling-interest shareholders and the related consolidated subsidiary												(3)
Transactions between Citigroup and the noncontrolling-interest shareholders												(50)
Dividends paid to noncontrolling-interest shareholders												(44)
Other comprehensive income (loss)											1,986	82
Net change in noncontrolling interests												(35)
Balance, end of period at Sep. 30, 2017		228,622	227,634	19,253	208,381	107,927	155,174		(24,829)		(29,891)	988
Balance, beginning of period at Jun. 30, 2017											(29,899)
Increase (Decrease) in Stockholders' Equity
Citigroup’s net income		4,132
Preferred dividends		(272)
Other comprehensive income (loss)											8
Balance, end of period at Sep. 30, 2017		$ 228,622	$ 227,634	$ 19,253	$ 208,381	$ 107,927	$ 155,174		$ (24,829)		$ (29,891)	$ 988

[1] See Note 1 to the Consolidated Financial Statements for additional details.

[2] Includes treasury stock related to (i) certain activity on employee stock option program exercises where the employee delivers existing shares to cover the option exercise, or (ii) under Citi’s employee restricted or deferred stock programs where shares are withheld to satisfy tax requirements.

[3] For the nine months ended September 30, 2017 and 2016, primarily consists of open market purchases under Citi’s Board of Directors-approved common stock repurchase program.

[4] Includes the impact of ASU 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. See Note 1 to the Consolidated Financial Statements.

[5] Common dividends declared were $0.16 per share in the first and second quarters and $0.32 per share in the third quarter of 2017. Common dividends declared were $0.05 per share in the first and second quarters and $0.16 per share in the third quarter of 2016.