CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Citigroup’s net income		$ 4,490	$ 3,872	$ 9,110	$ 7,962
Add: Citigroup's other comprehensive income
Net change in unrealized gains and losses on investment securities, net of taxes	[1],[2]	(498)	(27)	(1,556)	193
Net change in debt valuation adjustment (DVA), net of taxes	[2]	318	(84)	446	(144)
Net change in cash flow hedges, net of taxes		(101)	117	(323)	115
Benefit plans liability adjustment, net of taxes		301	(135)	389	(147)
Net change in foreign currency translation adjustment, net of taxes and hedges		(2,867)	643	(1,747)	1,961
Net change in excluded component of fair value hedges, net of taxes		(28)	0	(32)	0
Citigroup’s total other comprehensive income		(2,875)	514	(2,823)	1,978
Citigroup’s total comprehensive income		1,615	4,386	6,287	9,940
Add: Other comprehensive income attributable to noncontrolling interests		(57)	39	(43)	70
Add: Net income attributable to noncontrolling interests		26	32	48	42
Total comprehensive income		$ 1,584	$ 4,457	$ 6,292	$ 10,052

[1] For the three and six months ended June 30, 2018, respectively, amount represents the net change in unrealized gains and losses on available-for-sale (AFS) debt securities. Effective January 1, 2018, the AFS category is eliminated for equity securities under ASU 2016-01.

[2] See Note 1 to the Consolidated Financial Statements.