CONSOLIDATED STATEMENT OF INCOME - USD ($) shares in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues
Interest revenue		$ 76,510	$ 70,828	$ 61,579
Interest expense		29,163	24,266	16,518
Net interest revenue		47,347	46,562	45,061
Commissions and fees		11,746	11,857	12,707
Principal transactions		8,892	8,905	8,940
Administration and other fiduciary fees		3,411	3,580	3,584
Realized gains on sales of investments, net		1,474	421	778
Net impairment losses recognized in earnings		(32)	(132)	(63)
Other revenue		1,448	1,661	1,437
Total non-interest revenues		26,939	26,292	27,383
Total revenues, net of interest expense		74,286	72,854	72,444
Provisions for credit losses and for benefits and claims
Provision for loan losses		8,218	7,354	7,503
Policyholder benefits and claims		73	101	109
Provision (release) for unfunded lending commitments		92	113	(161)
Total provisions for credit losses and for benefits and claims		8,383	7,568	7,451
Operating expenses
Compensation and benefits		21,433	21,154	21,181
Premises and equipment		2,328	2,324	2,453
Technology/communication		7,077	7,193	6,909
Advertising and marketing		1,516	1,545	1,608
Other operating		9,648	9,625	10,081
Total operating expenses		42,002	41,841	42,232
Income (loss) from continuing operations before income taxes		23,901	23,445	22,761
Provision for income taxes		4,430	5,357	29,388
Income (loss) from continuing operations		19,471	18,088	(6,627)
Discontinued operations
Loss from discontinued operations		(31)	(26)	(104)
Provision (benefit) for income taxes		(27)	(18)	7
Loss from discontinued operations, net of taxes		(4)	(8)	(111)
Net income (loss) before attribution of noncontrolling interests		19,467	18,080	(6,738)
Noncontrolling interests		66	35	60
Citigroup’s net income (loss)		$ 19,401	$ 18,045	$ (6,798)
Basic earnings per share
Income (loss) from continuing operations (in dollars per share)	[1]	$ 8.08	$ 6.69	$ (2.94)
Loss from discontinued operations, net of taxes (in dollars per share)	[1]	0	0	(0.04)
Net income (loss) (in dollars per share)	[1]	$ 8.08	$ 6.69	$ (2.98)
Weighted average common shares outstanding (in shares)		2,249.2	2,493.3	2,698.5
Diluted earnings per share
Income (loss) from continuing operations (in dollars per share)		$ 8.04	$ 6.69	$ (2.94)
Income (loss) from discontinued operations, net of taxes (in dollars per share)		0	0	(0.04)
Net income (loss) (in dollars per share)		$ 8.04	$ 6.68	$ (2.98)
Adjusted weighted average common shares outstanding (in shares)		2,265.3	2,494.8	2,698.5

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