PERSONNEL EXPENSES AND DEFERRED EMPLOYEE BENEFITS - Actuarial Assumptions for Defined Benefit Plans (Details)	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Pension defined benefit plans \| Bottom of range
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Discount rate (in percent)	4.00%	3.40%	3.30%
Rate of compensation increase (in percent)	2.00%	2.00%	2.00%
Pension defined benefit plans \| Top of range
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Discount rate (in percent)	18.00%	17.00%	18.00%
Rate of compensation increase (in percent)	11.00%	11.00%	11.00%
Pension defined benefit plans \| Weighted average
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Discount rate (in percent)	5.44%	5.07%	5.02%
Rate of compensation increase (in percent)	3.05%	2.92%	2.93%
Other post-employment benefits and other long-term employee benefits ("OPEB") \| Bottom of range
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Discount rate (in percent)	3.40%	3.40%	3.30%
Rate of compensation increase (in percent)	2.00%	2.00%	2.00%
Other post-employment benefits and other long-term employee benefits ("OPEB") \| Top of range
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Discount rate (in percent)	12.00%	12.15%	10.15%
Rate of compensation increase (in percent)	5.00%	5.00%	4.80%
Other post-employment benefits and other long-term employee benefits ("OPEB") \| Weighted average
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Discount rate (in percent)	4.86%	4.73%	4.68%
Rate of compensation increase (in percent)	3.30%	3.24%	3.26%

The discount rate used as the significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit obligation, at present value; Actuarial assumptions [domain]]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-IssueDate 2025-01-01
-Paragraph 144
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The expected rate of salary increases used as a significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit plans [domain]; Defined benefit obligation, at present value; Actuarial assumptions [domain]]

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