CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Citigroup’s net income		$ 11,047	$ 19,401	$ 18,045
Add: Citigroup’s other comprehensive income (loss)
Net change in unrealized gains and losses on investment securities, net of taxes	[1]	3,585	1,985	(1,089)
Net change in debt valuation adjustment (DVA), net of taxes	[1]	(475)	(1,136)	1,113
Net change in cash flow hedges, net of taxes		1,470	851	(30)
Benefit plans liability adjustment, net of taxes	[2]	(55)	(552)	(74)
Net change in foreign currency translation adjustment, net of taxes and hedges		(250)	(321)	(2,362)
Net change in excluded component of fair value hedges, net of taxes		(15)	25	(57)
Citigroup’s total other comprehensive income (loss)		4,260	852	(2,499)
Citigroup’s total comprehensive income		15,307	20,253	15,546
Add: Other comprehensive income (loss) attributable to noncontrolling interests		26	0	(43)
Add: Net income attributable to noncontrolling interests		40	66	35
Total comprehensive income		$ 15,373	$ 20,319	$ 15,538

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

[2] See Note 8 to the Consolidated Financial Statements.