BASIS OF PRESENTATION (Policies)	3 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The unaudited interim Consolidated Financial Statements, including the Notes presented in this document, have been prepared in accordance with GAAP interim reporting requirements and, therefore, do not include all information and Notes included in the audited Consolidated Financial Statements in conformity with GAAP. The unaudited interim Consolidated Financial Statements and Notes presented in this document should be read in conjunction with the Company’s audited Consolidated Financial Statements and accompanying Notes included in the Company’s 2021 Form 10-K. The Company’s principal business activity is banking, conducted through its banking subsidiary CBNA.
Consolidation	The unaudited interim Consolidated Financial Statements include the accounts of Citizens and subsidiaries in which Citizens has a controlling financial interest. All intercompany transactions and balances have been eliminated. The Company has evaluated its unconsolidated entities and does not believe that any entity in which it has an interest, but does not currently consolidate, meets the requirements to be consolidated as a variable interest entity. The unaudited interim Consolidated Financial Statements include all adjustments, consisting of normal recurring adjustments, necessary for a fair presentation of the results for the interim periods. The results for interim periods are not necessarily indicative of results for a full year.
Use of Estimates	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Material estimates that are particularly susceptible to significant change in the near-term relate to the determination of the ACL.