OPERATING SEGMENTS (Details) $ in Millions			3 Months Ended				6 Months Ended
		Mar. 01, 2023 USD ($)	Jun. 30, 2024 USD ($)	Mar. 31, 2024 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Jun. 30, 2024 USD ($) segment	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment							5
Segment Reporting Information [Line Items]
Net interest income			$ 13,493		$ 13,900		$ 27,000	$ 27,248
Non-interest revenue			6,646		5,536		14,243	13,635
Total revenues, net of interest expense			20,139		19,436		41,243	40,883
Provisions for credit losses and for benefits and claims	[1]		2,476		1,824		4,841	3,799
Provision (benefits) for income taxes			1,047		1,090		2,183	2,621
Income (loss) from continuing operations			3,263		2,952		6,671	7,604
Identifiable assets			2,405,686				2,405,686		$ 2,411,834
Average loans			680,000		654,000		679,000	654,000
Average deposits			1,310,000		1,338,000		1,318,000	1,351,000
Sold | India
Segment Reporting Information [Line Items]
Pretax loss on sale of business		$ (1,000)
Loss on sale of business, after-tax		$ (717)
Operating expenses, before tax						$ 1,059
Operating expenses, after tax						$ 727
Held for sale | Mexico and Asia Exit Markets
Segment Reporting Information [Line Items]
Operating expenses, before tax			85	$ 110	79
Operating expenses, after tax			58	$ 77	57
Operating Segments
Segment Reporting Information [Line Items]
Income (loss) from continuing operations			3,295		3,044		6,797	7,048
Operating Segments | Services
Segment Reporting Information [Line Items]
Net interest income			3,225		3,243		6,542	6,369
Non-interest revenue			1,455		1,312		2,904	2,580
Total revenues, net of interest expense			4,680		4,555		9,446	8,949
Provisions for credit losses and for benefits and claims			(27)		223		37	209
Provision (benefits) for income taxes			475		596		996	1,286
Income (loss) from continuing operations			1,498		1,230		3,013	2,539
Identifiable assets			569,000				569,000		586,000
Average loans			82,000		80,000		82,000	80,000
Average deposits			804,000		814,000		806,000	822,000
Operating Segments | Markets
Segment Reporting Information [Line Items]
Net interest income			2,038		1,999		3,744	3,551
Non-interest revenue			3,048		2,780		6,699	6,984
Total revenues, net of interest expense			5,086		4,779		10,443	10,535
Provisions for credit losses and for benefits and claims			(11)		(17)		188	67
Provision (benefits) for income taxes			323		312		676	955
Income (loss) from continuing operations			1,469		1,139		2,890	3,001
Identifiable assets			1,023,000				1,023,000		1,008,000
Average loans			119,000		107,000		120,000	109,000
Average deposits			25,000		23,000		25,000	23,000
Operating Segments | Banking
Segment Reporting Information [Line Items]
Net interest income			527		542		1,109	1,055
Non-interest revenue			1,100		637		2,254	1,309
Total revenues, net of interest expense			1,627		1,179		3,363	2,364
Provisions for credit losses and for benefits and claims			(32)		(148)		(161)	(271)
Provision (benefits) for income taxes			119		16		278	36
Income (loss) from continuing operations			409		51		936	108
Identifiable assets			147,000				147,000		148,000
Average loans			89,000		93,000		89,000	94,000
Average deposits			1,000		1,000		1,000	1,000
Operating Segments | USPB
Segment Reporting Information [Line Items]
Net interest income			5,103		4,883		10,329	9,737
Non-interest revenue			(184)		(264)		(232)	(407)
Total revenues, net of interest expense			4,919		4,619		10,097	9,330
Provisions for credit losses and for benefits and claims			2,315		1,525		4,519	3,174
Provision (benefits) for income taxes			41		135		149	266
Income (loss) from continuing operations			121		461		468	863
Identifiable assets			242,000				242,000		242,000
Average loans			206,000		189,000		205,000	186,000
Average deposits			93,000		113,000		97,000	112,000
Operating Segments | Wealth
Segment Reporting Information [Line Items]
Net interest income			1,047		1,096		2,028	2,207
Non-interest revenue			767		680		1,479	1,319
Total revenues, net of interest expense			1,814		1,776		3,507	3,526
Provisions for credit losses and for benefits and claims			(9)		53		(179)	(5)
Provision (benefits) for income taxes			71		26		117	72
Income (loss) from continuing operations			210		84		385	266
Identifiable assets			228,000				228,000		229,000
Average loans			150,000		150,000		150,000	150,000
Average deposits			316,000		311,000		316,000	314,000
All Other
Segment Reporting Information [Line Items]
Net interest income			1,553		2,137		3,248	4,329
Non-interest revenue			427		397		1,118	838
Total revenues, net of interest expense			1,980		2,534		4,366	5,167
Provisions for credit losses and for benefits and claims			243		200		429	645
Provision (benefits) for income taxes			35		(14)		23	(318)
Income (loss) from continuing operations			(412)		79		(895)	271
Identifiable assets			197,000				197,000		$ 199,000
Average loans			34,000		35,000		33,000	35,000
Average deposits			71,000		76,000		73,000	79,000
Reconciling Items
Segment Reporting Information [Line Items]
Net interest income			0		0		0	0
Non-interest revenue			33		(6)		21	1,012
Total revenues, net of interest expense			33		(6)		21	1,012
Provisions for credit losses and for benefits and claims			(3)		(12)		8	(20)
Provision (benefits) for income taxes			(17)		19		(56)	324
Income (loss) from continuing operations			$ (32)		$ (92)		$ (126)	$ 556

[1] This total excludes the provision for credit losses on AFS debt securities, which is disclosed separately above.