CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Citigroup’s net income		$ 4,622	$ 4,133	$ 13,732	$ 12,095
Add: Citigroup's other comprehensive income
Net change in unrealized gains and losses on investment securities, net of taxes	[1],[2]	(605)	(66)	(2,161)	127
Net change in debt valuation adjustment (DVA), net of taxes	[2]	(287)	(123)	159	(267)
Net change in cash flow hedges, net of taxes		(74)	8	(397)	123
Benefit plans liability adjustment, net of taxes		26	(29)	415	(176)
Net change in foreign currency translation adjustment, net of taxes and hedges		(221)	218	(1,968)	2,179
Net change in excluded component of fair value hedges, net of taxes		10	0	(22)	0
Citigroup’s total other comprehensive income		(1,151)	8	(3,974)	1,986
Citigroup’s total comprehensive income		3,471	4,141	9,758	14,081
Add: Other comprehensive income attributable to noncontrolling interests		8	12	(35)	82
Add: Net income attributable to noncontrolling interests		3	(1)	51	41
Total comprehensive income		$ 3,482	$ 4,152	$ 9,774	$ 14,204

[1] For the three and nine months ended September 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.