LOANS - Consumer Troubled Debt Restructurings (Details) - Consumer $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) loan	Dec. 31, 2021 USD ($) loan
Loans receivable
Period within which default occurred post-modification	1 year
Number of days past due, non-accrual status	60 days
Residential first mortgages
Loans receivable
Number of days past due, non-accrual status	90 days
Home equity loans
Loans receivable
Number of days past due, non-accrual status	90 days
Credit cards
Loans receivable
Number of days past due, non-accrual status	180 days
Personal, small business and other
Loans receivable
Number of days past due, non-accrual status	90 days
In North America offices
Loans receivable
Number of loans modified | loan	178,411	167,624
Post-modification recorded investment	$ 1,085.0	$ 1,056.0
Loans in default	$ 290.0	$ 321.0
In North America offices | Residential first mortgages
Loans receivable
Number of loans modified | loan	1,133	1,335
Post-modification recorded investment	$ 263.0	$ 230.0
Average interest rate reduction (as a percent)	0.00%	1.00%
Post-modification recorded investment for borrowers that have gone through Chapter 7 bankruptcy	$ 5.0	$ 15.0
Loans in default	35.0	57.0
In North America offices | Residential first mortgages | New OCC guidance
Loans receivable
Post-modification recorded investment for borrowers that have gone through Chapter 7 bankruptcy	$ 3.8	$ 5.0
In North America offices | Home equity loans
Loans receivable
Number of loans modified | loan	451	191
Post-modification recorded investment	$ 40.0	$ 19.0
Average interest rate reduction (as a percent)	0.00%	0.00%
Loans in default	$ 4.0	$ 8.0
In North America offices | Credit cards
Loans receivable
Number of loans modified | loan	176,252	165,098
Post-modification recorded investment	$ 775.0	$ 794.0
Average interest rate reduction (as a percent)	18.00%	18.00%
Loans in default	$ 250.0	$ 252.0
In North America offices | Personal, small business and other
Loans receivable
Number of loans modified | loan	575	1,000
Post-modification recorded investment	$ 7.0	$ 13.0
Average interest rate reduction (as a percent)	5.00%	3.00%
Loans in default	$ 1.0	$ 4.0
In offices outside the U.S.
Loans receivable
Number of loans modified | loan	19,121	104,385
Post-modification recorded investment	$ 118.0	$ 627.0
Loans in default	$ 25.0	$ 286.0
In offices outside the U.S. | Residential first mortgages
Loans receivable
Number of loans modified | loan	683	1,975
Post-modification recorded investment	$ 21.0	$ 86.0
Average interest rate reduction (as a percent)	0.00%	0.00%
Loans in default	$ 10.0	$ 38.0
In offices outside the U.S. | Credit cards
Loans receivable
Number of loans modified | loan	16,006	74,202
Post-modification recorded investment	$ 68.0	$ 339.0
Average interest rate reduction (as a percent)	25.00%	13.00%
Loans in default	$ 12.0	$ 152.0
In offices outside the U.S. | Personal, small business and other
Loans receivable
Number of loans modified | loan	2,432	28,208
Post-modification recorded investment	$ 29.0	$ 202.0
Average interest rate reduction (as a percent)	8.00%	10.00%
Loans in default	$ 3.0	$ 96.0
Deferred principal | In North America offices
Loans receivable
Post-modification recorded investment	0.0	0.0
Deferred principal | In North America offices | Residential first mortgages
Loans receivable
Post-modification recorded investment	0.0	0.0
Deferred principal | In North America offices | Home equity loans
Loans receivable
Post-modification recorded investment	0.0	0.0
Deferred principal | In North America offices | Credit cards
Loans receivable
Post-modification recorded investment	0.0	0.0
Deferred principal | In North America offices | Personal, small business and other
Loans receivable
Post-modification recorded investment	0.0	0.0
Deferred principal | In offices outside the U.S.
Loans receivable
Post-modification recorded investment	0.0	0.0
Deferred principal | In offices outside the U.S. | Residential first mortgages
Loans receivable
Post-modification recorded investment	0.0	0.0
Deferred principal | In offices outside the U.S. | Credit cards
Loans receivable
Post-modification recorded investment	0.0	0.0
Deferred principal | In offices outside the U.S. | Personal, small business and other
Loans receivable
Post-modification recorded investment	0.0	0.0
Contingent principal forgiveness | In North America offices
Loans receivable
Post-modification recorded investment	0.0	0.0
Contingent principal forgiveness | In North America offices | Residential first mortgages
Loans receivable
Post-modification recorded investment	0.0	0.0
Contingent principal forgiveness | In North America offices | Home equity loans
Loans receivable
Post-modification recorded investment	0.0	0.0
Contingent principal forgiveness | In North America offices | Credit cards
Loans receivable
Post-modification recorded investment	0.0	0.0
Contingent principal forgiveness | In North America offices | Personal, small business and other
Loans receivable
Post-modification recorded investment	0.0	0.0
Contingent principal forgiveness | In offices outside the U.S.
Loans receivable
Post-modification recorded investment	0.0	0.0
Contingent principal forgiveness | In offices outside the U.S. | Residential first mortgages
Loans receivable
Post-modification recorded investment	0.0	0.0
Contingent principal forgiveness | In offices outside the U.S. | Credit cards
Loans receivable
Post-modification recorded investment	0.0	0.0
Contingent principal forgiveness | In offices outside the U.S. | Personal, small business and other
Loans receivable
Post-modification recorded investment	0.0	0.0
Principal forgiveness | In North America offices
Loans receivable
Post-modification recorded investment	0.0	0.0
Principal forgiveness | In North America offices | Residential first mortgages
Loans receivable
Post-modification recorded investment	0.0	0.0
Principal forgiveness | In North America offices | Home equity loans
Loans receivable
Post-modification recorded investment	0.0	0.0
Principal forgiveness | In North America offices | Credit cards
Loans receivable
Post-modification recorded investment	0.0	0.0
Principal forgiveness | In North America offices | Personal, small business and other
Loans receivable
Post-modification recorded investment	0.0	0.0
Principal forgiveness | In offices outside the U.S.
Loans receivable
Post-modification recorded investment	2.0	20.0
Principal forgiveness | In offices outside the U.S. | Residential first mortgages
Loans receivable
Post-modification recorded investment	0.0	0.0
Principal forgiveness | In offices outside the U.S. | Credit cards
Loans receivable
Post-modification recorded investment	1.0	13.0
Principal forgiveness | In offices outside the U.S. | Personal, small business and other
Loans receivable
Post-modification recorded investment	$ 1.0	$ 7.0