LOANS - Non-Accrual Corporate Loans (Details) - Corporate loans - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Financing Receivable, Impaired [Line Items]
Recorded investment	$ 1,016		$ 953
Related specific allowance	417		323
Non-accrual loans for which there is no ACLL	941		1,048
Interest income recognized	13	$ 8
Commercial and industrial
Financing Receivable, Impaired [Line Items]
Recorded investment	897		788
Related specific allowance	365		295
Non-accrual loans for which there is no ACLL	306		353
Financial institutions
Financing Receivable, Impaired [Line Items]
Recorded investment	10		0
Related specific allowance	2		0
Non-accrual loans for which there is no ACLL	114		65
Mortgage and real estate
Financing Receivable, Impaired [Line Items]
Recorded investment	20		44
Related specific allowance	4		4
Non-accrual loans for which there is no ACLL	500		583
Lease financing
Financing Receivable, Impaired [Line Items]
Non-accrual loans for which there is no ACLL	0		0
Other
Financing Receivable, Impaired [Line Items]
Recorded investment	89		121
Related specific allowance	46		24
Non-accrual loans for which there is no ACLL	$ 21		$ 47

CITIGROUP INC 10-Q