SUBSIDIARY GUARANTEES - Summarized Balance Sheet (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Condensed Balance Sheet Statements
Cash	$ 26,548	$ 30,577	$ 26,502
Securities borrowed and purchased under resale agreements	335,059	365,401
Trading account assets	406,368	334,114
Other assets	96,824	103,743
Total assets	2,368,477	2,416,676
Securities loaned and sold under repurchase agreements	256,770	202,444
Trading account liabilities	164,624	170,647
Short-term borrowings	43,166	47,096
Long-term debt	275,760	271,606
Other liabilities	69,380	87,873
Stockholders’ equity	210,195	201,838	$ 199,117
Total liabilities and equity	2,368,477	2,416,676
Citigroup Inc.
Condensed Balance Sheet Statements
Long-term debt	160,571	166,257
Citigroup Inc. | Reportable legal entities
Condensed Balance Sheet Statements
Cash	3,018	3,015
Securities borrowed and purchased under resale agreements	0	0
Trading account assets	557	306
Advances to subsidiaries	151,911	146,843
Other assets	14,766	13,788
Total assets	393,206	384,968
Securities loaned and sold under repurchase agreements	0	0
Trading account liabilities	205	604
Short-term borrowings	1,500	0
Long-term debt	160,571	166,257
Advances from subsidiaries	17,803	14,562
Other liabilities	3,624	2,356
Stockholders’ equity	209,503	201,189
Total liabilities and equity	393,206	384,968
Citigroup Inc. | Reportable legal entities | Subsidiary Holding Company
Condensed Balance Sheet Statements
Investments in subsidiaries	175,310	172,721
Citigroup Inc. | Reportable legal entities | Non-Bank Subsidiaries
Condensed Balance Sheet Statements
Investments in subsidiaries	47,644	48,295
CGMHI | Reportable legal entities
Condensed Balance Sheet Statements
Cash	20,385	27,122
Securities borrowed and purchased under resale agreements	271,275	306,273
Trading account assets	260,593	209,957
Advances to subsidiaries	0	0
Other assets	179,700	163,819
Total assets	731,953	707,171
Securities loaned and sold under repurchase agreements	294,354	245,916
Trading account liabilities	104,799	115,929
Short-term borrowings	25,929	43,850
Long-term debt	184,859	172,068
Advances from subsidiaries	0	0
Other liabilities	83,858	90,570
Stockholders’ equity	38,154	38,838
Total liabilities and equity	731,953	707,171
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