CONDENSED CONSOLIDATING FINANCIAL STATEMENTS - Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities of continuing operations		$ (4,170)	$ 59,185
Cash flows from investing activities of continuing operations
Change in securities borrowed and purchased under agreements to resell		(21,926)	(42,984)
Change in loans		(5,788)	6,613
Proceeds from sales and securitizations of loans		3,077	1,134
Proceeds from divestitures	[1]	3,242	0
Available-for-sale debt securities
Purchases of investments	[2]	(177,306)	(164,613)
Proceeds from sales of investments	[2]	86,454	96,022
Proceeds from maturities of investments	[2]	118,951	90,415
Held-to-maturity debt securities
Purchases of investments	[2]	(39,288)	(112,883)
Proceeds from maturities of investments	[2]	9,913	16,946
Changes in investments and advances—intercompany		0	0
Other investing activities		(4,151)	(2,719)
Net cash used in investing activities of continuing operations		(26,822)	(112,069)
Cash flows from financing activities of continuing operations
Dividends paid		(3,777)	(3,959)
Issuance of preferred stock		0	2,300
Redemption of preferred stock		0	(3,785)
Treasury stock acquired		(3,250)	(7,448)
Proceeds (repayments) from issuance of long-term debt, net		38,448	(2,511)
Proceeds (repayments) from issuance of long-term debt—intercompany, net		0	0
Change in deposits		8,947	73,769
Change in securities loaned and sold under agreements to repurchase		12,144	9,659
Change in short-term borrowings		19,395	169
Net change in short-term borrowings and other advances—intercompany		0	0
Capital contributions from (to) parent		0	0
Other financing activities		(339)	(328)
Net cash provided by financing activities of continuing operations		71,568	67,866
Effect of exchange rate changes on cash and due from banks		(3,002)	(789)
Change in cash, due from banks and deposits with banks		37,574	14,193
Cash, due from banks and deposits with banks at beginning of period		262,033	309,615
Cash, due from banks and deposits with banks at end of period		299,607	323,808
Cash and due from banks		26,502	28,906	$ 27,515
Deposits with banks, net of allowance		273,105	294,902	234,518
Cash, due from banks and deposits with banks at end of period		299,607	323,808	262,033
Supplemental disclosure of cash flow information for continuing operations
Cash paid (received) during the period for income taxes		2,684	3,063
Cash paid during the period for interest		12,557	5,983
Non-cash investing and financing activities
Transfer of investment securities from AFS to HTM	[1],[3]	21,688	0
Decrease in net loans associated with divestitures reclassified to HFS	[1],[3]	16,956	8,291
Decrease in goodwill associated with divestitures reclassified to HFS	[1],[3]	876	0
Transfers to loans HFS (Other assets) from loans	[1],[3]	4,037	5,329
Decrease in deposits associated with divestitures reclassified to HFS	[1]	19,691	6,912
Decrease in long-term debt associated with divestitures reclassified to HFS	[1]	0	521
Reportable legal entities | Citigroup parent company
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities of continuing operations		(3,688)	3,604
Cash flows from investing activities of continuing operations
Change in securities borrowed and purchased under agreements to resell		0	0
Change in loans		0	0
Proceeds from sales and securitizations of loans		0	0
Proceeds from divestitures		0
Available-for-sale debt securities
Purchases of investments		0	0
Proceeds from sales of investments		0	0
Proceeds from maturities of investments		0	0
Held-to-maturity debt securities
Purchases of investments		0	0
Proceeds from maturities of investments		0	0
Changes in investments and advances—intercompany		(1,070)	3,374
Other investing activities		0	0
Net cash used in investing activities of continuing operations		(1,070)	3,374
Cash flows from financing activities of continuing operations
Dividends paid		(3,777)	(3,959)
Issuance of preferred stock			2,300
Redemption of preferred stock			(3,785)
Treasury stock acquired		(3,250)	(7,448)
Proceeds (repayments) from issuance of long-term debt, net		11,386	4,660
Proceeds (repayments) from issuance of long-term debt—intercompany, net		0	0
Change in deposits		0	0
Change in securities loaned and sold under agreements to repurchase		0	0
Change in short-term borrowings		0	0
Net change in short-term borrowings and other advances—intercompany		246	1,074
Capital contributions from (to) parent		0	0
Other financing activities		(339)	(328)
Net cash provided by financing activities of continuing operations		4,266	(7,486)
Effect of exchange rate changes on cash and due from banks		0	0
Change in cash, due from banks and deposits with banks		(492)	(508)
Cash, due from banks and deposits with banks at beginning of period		3,517	4,516
Cash, due from banks and deposits with banks at end of period		3,025	4,008
Cash and due from banks		25	8
Deposits with banks, net of allowance		3,000	4,000
Cash, due from banks and deposits with banks at end of period		3,025	4,008	3,517
Supplemental disclosure of cash flow information for continuing operations
Cash paid (received) during the period for income taxes		(1,030)	(1,757)
Cash paid during the period for interest		1,308	2,307
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	0
Decrease in goodwill associated with divestitures reclassified to HFS		0
Transfers to loans HFS (Other assets) from loans		0	0
Decrease in deposits associated with divestitures reclassified to HFS		0	0
Decrease in long-term debt associated with divestitures reclassified to HFS			0
Reportable legal entities | CGMHI
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities of continuing operations		(29,719)	30,413
Cash flows from investing activities of continuing operations
Change in securities borrowed and purchased under agreements to resell		(11,947)	(40,065)
Change in loans		0	0
Proceeds from sales and securitizations of loans		0	0
Proceeds from divestitures		0
Available-for-sale debt securities
Purchases of investments		0	0
Proceeds from sales of investments		0	0
Proceeds from maturities of investments		0	0
Held-to-maturity debt securities
Purchases of investments		0	0
Proceeds from maturities of investments		0	0
Changes in investments and advances—intercompany		(23,189)	(9,743)
Other investing activities		(45)	(42)
Net cash used in investing activities of continuing operations		(35,181)	(49,850)
Cash flows from financing activities of continuing operations
Dividends paid		(271)	(195)
Issuance of preferred stock			0
Redemption of preferred stock			0
Treasury stock acquired		0	0
Proceeds (repayments) from issuance of long-term debt, net		30,094	11,336
Proceeds (repayments) from issuance of long-term debt—intercompany, net		12,847	9,084
Change in deposits			0
Change in securities loaned and sold under agreements to repurchase		14,916	(2,397)
Change in short-term borrowings		7,058	2,224
Net change in short-term borrowings and other advances—intercompany		207	1,253
Capital contributions from (to) parent		380	(19)
Other financing activities		4	0
Net cash provided by financing activities of continuing operations		65,235	21,286
Effect of exchange rate changes on cash and due from banks		0	0
Change in cash, due from banks and deposits with banks		335	1,849
Cash, due from banks and deposits with banks at beginning of period		26,665	20,112
Cash, due from banks and deposits with banks at end of period		27,000	21,961
Cash and due from banks		7,308	6,998
Deposits with banks, net of allowance		19,692	14,963
Cash, due from banks and deposits with banks at end of period		27,000	21,961	26,665
Supplemental disclosure of cash flow information for continuing operations
Cash paid (received) during the period for income taxes		228	809
Cash paid during the period for interest		4,785	1,687
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	0
Decrease in goodwill associated with divestitures reclassified to HFS		0
Transfers to loans HFS (Other assets) from loans		0	0
Decrease in deposits associated with divestitures reclassified to HFS		0	0
Decrease in long-term debt associated with divestitures reclassified to HFS			0
Reportable legal entities | Other Citigroup subsidiaries and eliminations
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities of continuing operations		29,237	25,168
Cash flows from investing activities of continuing operations
Change in securities borrowed and purchased under agreements to resell		(9,979)	(2,919)
Change in loans		(5,788)	6,613
Proceeds from sales and securitizations of loans		3,077	1,134
Proceeds from divestitures		3,242
Available-for-sale debt securities
Purchases of investments		(177,306)	(164,613)
Proceeds from sales of investments		86,454	96,022
Proceeds from maturities of investments		118,951	90,415
Held-to-maturity debt securities
Purchases of investments		(39,288)	(112,883)
Proceeds from maturities of investments		9,913	16,946
Changes in investments and advances—intercompany		24,259	6,369
Other investing activities		(4,106)	(2,677)
Net cash used in investing activities of continuing operations		9,429	(65,593)
Cash flows from financing activities of continuing operations
Dividends paid		271	195
Issuance of preferred stock			0
Redemption of preferred stock			0
Treasury stock acquired		0	0
Proceeds (repayments) from issuance of long-term debt, net		(3,032)	(18,507)
Proceeds (repayments) from issuance of long-term debt—intercompany, net		(12,847)	(9,084)
Change in deposits		8,947	73,769
Change in securities loaned and sold under agreements to repurchase		(2,772)	12,056
Change in short-term borrowings		12,337	(2,055)
Net change in short-term borrowings and other advances—intercompany		(453)	(2,327)
Capital contributions from (to) parent		(380)	19
Other financing activities		(4)	0
Net cash provided by financing activities of continuing operations		2,067	54,066
Effect of exchange rate changes on cash and due from banks		(3,002)	(789)
Change in cash, due from banks and deposits with banks		37,731	12,852
Cash, due from banks and deposits with banks at beginning of period		231,851	284,987
Cash, due from banks and deposits with banks at end of period		269,582	297,839
Cash and due from banks		19,169	21,900
Deposits with banks, net of allowance		250,413	275,939
Cash, due from banks and deposits with banks at end of period		269,582	297,839	231,851
Supplemental disclosure of cash flow information for continuing operations
Cash paid (received) during the period for income taxes		3,486	4,011
Cash paid during the period for interest		6,464	1,989
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	8,291
Decrease in goodwill associated with divestitures reclassified to HFS		876
Transfers to loans HFS (Other assets) from loans		4,037	5,329
Decrease in deposits associated with divestitures reclassified to HFS		19,691	6,912
Decrease in long-term debt associated with divestitures reclassified to HFS			521
Consolidating adjustments
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities of continuing operations		0	0
Cash flows from investing activities of continuing operations
Change in securities borrowed and purchased under agreements to resell		0	0
Change in loans		0	0
Proceeds from sales and securitizations of loans		0	0
Proceeds from divestitures
Available-for-sale debt securities
Purchases of investments		0	0
Proceeds from sales of investments		0	0
Proceeds from maturities of investments		0	0
Held-to-maturity debt securities
Purchases of investments		0	0
Proceeds from maturities of investments		0	0
Changes in investments and advances—intercompany		0	0
Other investing activities		0	0
Net cash used in investing activities of continuing operations		0	0
Cash flows from financing activities of continuing operations
Dividends paid		0	0
Issuance of preferred stock			0
Redemption of preferred stock			0
Treasury stock acquired		0	0
Proceeds (repayments) from issuance of long-term debt, net		0	0
Proceeds (repayments) from issuance of long-term debt—intercompany, net		0	0
Change in deposits		0	0
Change in securities loaned and sold under agreements to repurchase		0	0
Change in short-term borrowings		0	0
Net change in short-term borrowings and other advances—intercompany		0	0
Capital contributions from (to) parent		0	0
Other financing activities		0	0
Net cash provided by financing activities of continuing operations		0	0
Effect of exchange rate changes on cash and due from banks		0	0
Change in cash, due from banks and deposits with banks		0	0
Cash, due from banks and deposits with banks at beginning of period		0	0
Cash, due from banks and deposits with banks at end of period		0	0
Cash and due from banks		0	0
Deposits with banks, net of allowance		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 (received) during the period for income taxes		0	0
Cash paid during the period for interest		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	0
Decrease in goodwill associated with divestitures reclassified to HFS		0
Transfers to loans HFS (Other assets) from loans		0	0
Decrease in deposits associated with divestitures reclassified to HFS		$ 0	0
Decrease in long-term debt associated with divestitures reclassified to HFS			$ 0

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

[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 available-for-sale debt securities and held-to-maturity debt securities. Citi had no sales of held-to-maturity debt securities during the periods presented.

[3] 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 23 for more information and balances as of September 30, 2022.