CONSOLIDATED STATEMENT OF INCOME - USD ($) shares in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues
Interest revenue		$ 58,089	$ 76,510	$ 70,828
Interest expense		14,541	29,163	24,266
Net interest revenue		43,548	47,347	46,562
Commissions and fees		11,385	11,746	11,857
Principal transactions		13,885	8,892	8,905
Administration and other fiduciary fees		3,472	3,411	3,580
Realized gains on sales of investments, net		1,756	1,474	421
Impairment losses on investments:
Impairment losses on investments and other assets		(165)	(32)	(132)
Provision for credit losses on AFS debt securities	[1]	(3)	0	0
Net impairment losses recognized in earnings		(168)	(32)	(132)
Other revenue		420	1,448	1,661
Total non-interest revenues		30,750	26,939	26,292
Total revenues, net of interest expense		74,298	74,286	72,854
Provisions for credit losses and for benefits and claims
Provision for credit losses on loans		15,922	8,218	7,354
Provision for credit losses on held-to-maturity (HTM) debt securities		7	0	0
Provision for credit losses on other assets		7	0	0
Policyholder benefits and claims		113	73	101
Provision for credit losses on unfunded lending commitments		1,446	92	113
Total provisions for credit losses and for benefits and claims		17,495	8,383	7,568
Operating expenses
Compensation and benefits		22,214	21,433	21,154
Premises and equipment		2,333	2,328	2,324
Technology/communication		7,383	7,077	7,193
Advertising and marketing		1,217	1,516	1,545
Other operating		10,024	9,648	9,625
Total operating expenses		43,171	42,002	41,841
Income from continuing operations before income taxes		13,632	23,901	23,445
Provision for income taxes		2,525	4,430	5,357
Income from continuing operations		11,107	19,471	18,088
Discontinued operations
Loss from discontinued operations		(20)	(31)	(26)
Provision (benefit) for income taxes		0	(27)	(18)
Loss from discontinued operations, net of taxes		(20)	(4)	(8)
Net income before attribution of noncontrolling interests		11,087	19,467	18,080
Noncontrolling interests		40	66	35
Citigroup’s net income		$ 11,047	$ 19,401	$ 18,045
Basic earnings per share
Income from continuing operations (in dollars per share)	[2]	$ 4.75	$ 8.08	$ 6.69
Loss from discontinued operations, net of taxes (in dollars per share)	[2]	(0.01)	0	0
Net income (in dollars per share)	[2]	$ 4.74	$ 8.08	$ 6.69
Weighted average common shares outstanding (in shares)		2,085.8	2,249.2	2,493.3
Diluted earnings per share
Income from continuing operations (in dollars per share)	[2]	$ 4.73	$ 8.04	$ 6.69
Income (loss) from discontinued operations, net of taxes (in dollars per share)	[2]	(0.01)	0	0
Net income (in dollars per share)	[2]	$ 4.72	$ 8.04	$ 6.68
Adjusted weighted average common shares outstanding (in shares)		2,099.0	2,265.3	2,494.8

[1] In accordance with ASC 326.

[2] Due to rounding, earnings per share on continuing operations and discontinued operations may not sum to earnings per share on net income.