SUBSIDIARY GUARANTEES - Summarized Balance Sheet (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023
Condensed Balance Sheet Statements
Cash	$ 25,266	$ 27,342	$ 26,548
Securities borrowed and purchased under resale agreements	285,928	345,700
Trading account assets	458,072	411,756
Other assets	104,771	95,963
Total assets	2,430,663	2,411,834
Securities loaned and sold under repurchase agreements	278,377	278,107
Trading account liabilities	142,534	155,345
Short-term borrowings	41,340	37,457
Long-term debt	299,081	286,619
Other liabilities	68,244	75,835
Stockholders’ equity	209,902	206,251	$ 210,195
Total liabilities and equity	2,430,663	2,411,834
Citigroup Inc.
Condensed Balance Sheet Statements
Long-term debt	170,649	162,309
Citigroup Inc. | Reportable legal entities
Condensed Balance Sheet Statements
Cash	4,021	3,011
Securities borrowed and purchased under resale agreements	0	0
Trading account assets	435	461
Advances to subsidiaries	153,041	150,845
Other assets	14,941	14,202
Total assets	398,580	387,514
Securities loaned and sold under repurchase agreements	0	0
Trading account liabilities	329	300
Short-term borrowings	0	0
Long-term debt	170,649	162,309
Advances from subsidiaries	15,838	16,724
Other liabilities	2,681	2,728
Stockholders’ equity	209,083	205,453
Total liabilities and equity	398,580	387,514
Citigroup Inc. | Reportable legal entities | Subsidiary Holding Company
Condensed Balance Sheet Statements
Investments in subsidiaries	179,577	172,125
Citigroup Inc. | Reportable legal entities | Non-Bank Subsidiaries
Condensed Balance Sheet Statements
Investments in subsidiaries	46,565	46,870
CGMHI | Reportable legal entities
Condensed Balance Sheet Statements
Cash	20,604	23,756
Securities borrowed and purchased under resale agreements	229,063	283,174
Trading account assets	315,659	273,379
Advances to subsidiaries	0	0
Other assets	170,885	167,609
Total assets	736,211	747,918
Securities loaned and sold under repurchase agreements	300,713	309,862
Trading account liabilities	99,877	111,233
Short-term borrowings	26,629	20,481
Long-term debt	185,522	184,083
Advances from subsidiaries	0	0
Other liabilities	87,182	85,079
Stockholders’ equity	36,288	37,180
Total liabilities and equity	736,211	747,918
CGMHI | Reportable legal entities | Subsidiary Holding Company
Condensed Balance Sheet Statements
Investments in subsidiaries	0	0
CGMHI | Reportable legal entities | Non-Bank Subsidiaries
Condensed Balance Sheet Statements
Investments in subsidiaries	$ 0	$ 0