CONDENSED CONSOLIDATING FINANCIAL STATEMENTS - Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities of continuing operations	[1]	$ 25,069	$ 47,090	$ (23,488)
Available-for-sale debt securities
Purchases of investments	[1],[2]	(218,747)	(205,980)	(306,801)
Proceeds from sales of investments	[2]	79,687	125,895	144,035
Proceeds from maturities of investments	[2]	140,934	120,936	110,941
Held-to-maturity debt securities
Purchases of investments	[2]	(42,903)	(136,450)	(25,586)
Proceeds from maturities of investments	[2]	12,188	21,164	15,215
Change in loans		(16,591)	(1,173)	14,249
Proceeds from sales and securitizations of loans		4,709	2,918	1,495
Proceeds from divestitures	[3]	5,741	0	0
Change in securities borrowed and purchased under agreements to resell		(38,113)	(32,576)	(43,390)
Changes in investments and advances—intercompany		0	0	0
Other investing activities		(6,360)	(5,480)	(2,603)
Net cash used in investing activities of continuing operations	[1]	(79,455)	(110,746)	(92,445)
Cash flows from financing activities of continuing operations
Dividends paid		(5,003)	(5,198)	(5,352)
Issuance of preferred stock		0	3,300	2,995
Redemption of preferred stock		0	(3,785)	(1,500)
Treasury stock acquired		(3,250)	(7,601)	(2,925)
Proceeds (repayments) from issuance of long-term debt, net		47,663	(4,292)	13,056
Proceeds (repayments) from issuance of long-term debt—intercompany, net		0	0	0
Change in deposits		68,415	44,966	210,081
Change in securities loaned and sold under agreements to repurchase		11,159	(8,240)	33,186
Change in short-term borrowings		19,123	(1,541)	(15,535)
Net change in short-term borrowings and other advances—intercompany		0	0	0
Capital contributions from (to) parent		0	0
Other financing activities		(344)	(337)	(411)
Net cash provided by financing activities of continuing operations		137,763	17,272	233,595
Effect of exchange rate changes on cash and due from banks		(3,385)	(1,198)	(1,966)
Change in cash, due from banks and deposits with banks		79,992	(47,582)	115,696
Cash, due from banks and deposits with banks at beginning of year		262,033	309,615	193,919
Cash, due from banks and deposits with banks at end of year		342,025	262,033	309,615
Cash and due from banks (including segregated cash and other deposits)		30,577	27,515	26,349
Deposits with banks, net of allowance		311,448	234,518	283,266
Cash, due from banks and deposits with banks at end of period		342,025	262,033	309,615
Supplemental disclosure of cash flow information for continuing operations
Cash paid during the year for income taxes		3,733	4,028	4,797
Cash paid during the year for interest		22,615	7,143	12,094
Non-cash investing and financing activities
Transfer of investment securities from AFS to HTM	[3],[4]	21,688	0	0
Decrease in goodwill associated with divestitures reclassified to HFS	[3],[4]	876	0	0
Transfers to loans HFS (Other assets) from loans	[3],[4]	5,582	7,414	2,614
Decrease in long-term debt associated with divestitures reclassified to HFS	[3]	0	479	0
Decrease in deposits associated with divestitures reclassified to HFS	[3]	19,691	8,407	0
Decrease in net loans associated with divestitures reclassified to HFS	[3],[4]	16,956	9,945	0
Consolidating adjustments
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities of continuing operations		0	0	0
Available-for-sale debt securities
Purchases of investments		0	0	0
Proceeds from sales of investments		0	0	0
Proceeds from maturities of investments		0	0	0
Held-to-maturity debt securities
Purchases of investments		0	0	0
Proceeds from maturities of investments		0	0	0
Change in loans		0	0	0
Proceeds from sales and securitizations of loans		0	0	0
Proceeds from divestitures		0
Change in securities borrowed and purchased under agreements to resell		0	0	0
Changes in investments and advances—intercompany		0	0	0
Other investing activities		0	0	0
Net cash used in investing activities of continuing operations		0	0	0
Cash flows from financing activities of continuing operations
Dividends paid		0	0	0
Issuance of preferred stock		0	0	0
Redemption of preferred stock		0	0	0
Treasury stock acquired		0	0	0
Proceeds (repayments) from issuance of long-term debt, net		0	0	0
Proceeds (repayments) from issuance of long-term debt—intercompany, net		0	0	0
Change in deposits		0	0	0
Change in securities loaned and sold under agreements to repurchase		0	0	0
Change in short-term borrowings		0	0	0
Net change in short-term borrowings and other advances—intercompany		0	0	0
Capital contributions from (to) parent		0	0
Other financing activities		0	0	0
Net cash provided by financing activities of continuing operations		0	0	0
Effect of exchange rate changes on cash and due from banks		0	0	0
Change in cash, due from banks and deposits with banks		0	0	0
Cash, due from banks and deposits with banks at beginning of year		0	0	0
Cash, due from banks and deposits with banks at end of year		0	0	0
Cash and due from banks (including segregated cash and other deposits)		0	0	0
Deposits with banks, net of allowance		0	0	0
Cash, due from banks and deposits with banks at end of period		0	0	0
Supplemental disclosure of cash flow information for continuing operations
Cash paid during the year for income taxes		0	0	0
Cash paid during the year for interest		0	0	0
Non-cash investing and financing activities
Transfer of investment securities from AFS to HTM		0
Decrease in net loans associated with divestitures reclassified to HFS		0
Decrease in goodwill associated with divestitures reclassified to HFS		0
Transfers to loans HFS (Other assets) from loans		0	0	0
Decrease in long-term debt associated with divestitures reclassified to HFS			0
Decrease in deposits associated with divestitures reclassified to HFS		0	0
Decrease in net loans associated with divestitures reclassified to HFS			0
Citigroup parent company | Reportable legal entities
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities of continuing operations		156	3,947	5,002
Available-for-sale debt securities
Purchases of investments		0	0	0
Proceeds from sales of investments		0	0	0
Proceeds from maturities of investments		0	0	0
Held-to-maturity debt securities
Purchases of investments		0	0	0
Proceeds from maturities of investments		0	0	0
Change in loans		0	0	0
Proceeds from sales and securitizations of loans		0	0	0
Proceeds from divestitures		0
Change in securities borrowed and purchased under agreements to resell		0	0	0
Changes in investments and advances—intercompany		(7,815)	8,260	(5,584)
Other investing activities		0	0	0
Net cash used in investing activities of continuing operations		(7,815)	8,260	(5,584)
Cash flows from financing activities of continuing operations
Dividends paid		(5,003)	(5,198)	(5,352)
Issuance of preferred stock		0	3,300	2,995
Redemption of preferred stock		0	(3,785)	(1,500)
Treasury stock acquired		(3,250)	(7,601)	(2,925)
Proceeds (repayments) from issuance of long-term debt, net		14,661	(86)	16,798
Proceeds (repayments) from issuance of long-term debt—intercompany, net		0	0	0
Change in deposits		0	0	0
Change in securities loaned and sold under agreements to repurchase		0	0	0
Change in short-term borrowings		0	0	0
Net change in short-term borrowings and other advances—intercompany		1,093	501	(7,528)
Capital contributions from (to) parent		0	0
Other financing activities		(344)	(337)	(411)
Net cash provided by financing activities of continuing operations		7,157	(13,206)	2,077
Effect of exchange rate changes on cash and due from banks		0	0	0
Change in cash, due from banks and deposits with banks		(502)	(999)	1,495
Cash, due from banks and deposits with banks at beginning of year		3,517	4,516	3,021
Cash, due from banks and deposits with banks at end of year		3,015	3,517	4,516
Cash and due from banks (including segregated cash and other deposits)		15	17	16
Deposits with banks, net of allowance		3,000	3,500	4,500
Cash, due from banks and deposits with banks at end of period		3,015	3,517	4,516
Supplemental disclosure of cash flow information for continuing operations
Cash paid during the year for income taxes		(1,269)	(2,406)	(1,883)
Cash paid during the year for interest		1,309	3,101	2,681
Non-cash investing and financing activities
Transfer of investment securities from AFS to HTM		0
Decrease in net loans associated with divestitures reclassified to HFS		0
Decrease in goodwill associated with divestitures reclassified to HFS		0
Transfers to loans HFS (Other assets) from loans		0	0	0
Decrease in long-term debt associated with divestitures reclassified to HFS			0
Decrease in deposits associated with divestitures reclassified to HFS		0	0
Decrease in net loans associated with divestitures reclassified to HFS			0
CGMHI | Reportable legal entities
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities of continuing operations		(18,505)	43,227	(26,195)
Available-for-sale debt securities
Purchases of investments		0	0	0
Proceeds from sales of investments		0	0	0
Proceeds from maturities of investments		0	0	0
Held-to-maturity debt securities
Purchases of investments		0	0	0
Proceeds from maturities of investments		0	0	0
Change in loans		0	0	0
Proceeds from sales and securitizations of loans		0	0	0
Proceeds from divestitures		0
Change in securities borrowed and purchased under agreements to resell		(13,303)	(29,944)	(46,044)
Changes in investments and advances—intercompany		(33,929)	(9,040)	(6,917)
Other investing activities		(65)	(2)	(54)
Net cash used in investing activities of continuing operations		(47,297)	(38,986)	(53,015)
Cash flows from financing activities of continuing operations
Dividends paid		(281)	(196)	(172)
Issuance of preferred stock		0	0	0
Redemption of preferred stock		0	0	0
Treasury stock acquired		0	0	0
Proceeds (repayments) from issuance of long-term debt, net		34,162	15,071	6,349
Proceeds (repayments) from issuance of long-term debt—intercompany, net		11,089	14,410	3,960
Change in deposits		0	0	0
Change in securities loaned and sold under agreements to repurchase		11,901	(27,241)	79,322
Change in short-term borrowings		6,957	1,102	1,228
Net change in short-term borrowings and other advances—intercompany		2,038	(917)	(7,806)
Capital contributions from (to) parent		380	71
Other financing activities		12	12	0
Net cash provided by financing activities of continuing operations		66,258	2,312	82,881
Effect of exchange rate changes on cash and due from banks		0	0	0
Change in cash, due from banks and deposits with banks		456	6,553	3,671
Cash, due from banks and deposits with banks at beginning of year		26,665	20,112	16,441
Cash, due from banks and deposits with banks at end of year		27,121	26,665	20,112
Cash and due from banks (including segregated cash and other deposits)		8,403	7,724	6,709
Deposits with banks, net of allowance		18,718	18,941	13,403
Cash, due from banks and deposits with banks at end of period		27,121	26,665	20,112
Supplemental disclosure of cash flow information for continuing operations
Cash paid during the year for income taxes		363	919	1,138
Cash paid during the year for interest		9,936	2,210	4,516
Non-cash investing and financing activities
Transfer of investment securities from AFS to HTM		0
Decrease in net loans associated with divestitures reclassified to HFS		0
Decrease in goodwill associated with divestitures reclassified to HFS		0
Transfers to loans HFS (Other assets) from loans		0	0	0
Decrease in long-term debt associated with divestitures reclassified to HFS			0
Decrease in deposits associated with divestitures reclassified to HFS		0	0
Decrease in net loans associated with divestitures reclassified to HFS			0
Other Citigroup subsidiaries and eliminations | Reportable legal entities
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities of continuing operations		43,418	(84)	(2,295)
Available-for-sale debt securities
Purchases of investments		(218,747)	(205,980)	(306,801)
Proceeds from sales of investments		79,687	125,895	144,035
Proceeds from maturities of investments		140,934	120,936	110,941
Held-to-maturity debt securities
Purchases of investments		(42,903)	(136,450)	(25,586)
Proceeds from maturities of investments		12,188	21,164	15,215
Change in loans		(16,591)	(1,173)	14,249
Proceeds from sales and securitizations of loans		4,709	2,918	1,495
Proceeds from divestitures		5,741
Change in securities borrowed and purchased under agreements to resell		(24,810)	(2,632)	2,654
Changes in investments and advances—intercompany		41,744	780	12,501
Other investing activities		(6,295)	(5,478)	(2,549)
Net cash used in investing activities of continuing operations		(24,343)	(80,020)	(33,846)
Cash flows from financing activities of continuing operations
Dividends paid		281	196	172
Issuance of preferred stock		0	0	0
Redemption of preferred stock		0	0	0
Treasury stock acquired		0	0	0
Proceeds (repayments) from issuance of long-term debt, net		(1,160)	(19,277)	(10,091)
Proceeds (repayments) from issuance of long-term debt—intercompany, net		(11,089)	(14,410)	(3,960)
Change in deposits		68,415	44,966	210,081
Change in securities loaned and sold under agreements to repurchase		(742)	19,001	(46,136)
Change in short-term borrowings		12,166	(2,643)	(16,763)
Net change in short-term borrowings and other advances—intercompany		(3,131)	416	15,334
Capital contributions from (to) parent		(380)	(71)
Other financing activities		(12)	(12)	0
Net cash provided by financing activities of continuing operations		64,348	28,166	148,637
Effect of exchange rate changes on cash and due from banks		(3,385)	(1,198)	(1,966)
Change in cash, due from banks and deposits with banks		80,038	(53,136)	110,530
Cash, due from banks and deposits with banks at beginning of year		231,851	284,987	174,457
Cash, due from banks and deposits with banks at end of year		311,889	231,851	284,987
Cash and due from banks (including segregated cash and other deposits)		22,159	19,774	19,624
Deposits with banks, net of allowance		289,730	212,077	265,363
Cash, due from banks and deposits with banks at end of period		311,889	231,851	284,987
Supplemental disclosure of cash flow information for continuing operations
Cash paid during the year for income taxes		4,639	5,515	5,542
Cash paid during the year for interest		11,370	1,832	4,897
Non-cash investing and financing activities
Transfer of investment securities from AFS to HTM		21,688
Decrease in net loans associated with divestitures reclassified to HFS		16,956
Decrease in goodwill associated with divestitures reclassified to HFS		876
Transfers to loans HFS (Other assets) from loans		5,582	7,414	$ 2,614
Decrease in long-term debt associated with divestitures reclassified to HFS			479
Decrease in deposits associated with divestitures reclassified to HFS		$ 19,691	8,407
Decrease in net loans associated with divestitures reclassified to HFS			$ 9,945

[1] See “Statement of Cash Flows” in Note 1.

[2] Citi has revised the Consolidated Statement of Cash Flows to present purchases of investments, sales of investments and proceeds from maturities of investments separately between AFS debt securities and HTM debt securities. Citi had no sales of HTM debt securities during the periods presented.

[3] See Note 2 for further information on significant disposals.

[4] Operating and finance lease right-of-use assets and lease liabilities represent non-cash investing and financing activities, respectively, and are not included in the non-cash investing activities presented here. See Note 28 for more information and balances as of December 31, 2022 and 2021, respectively.