Basis of Presentation (Policy)	3 Months Ended
Basis of Presentation (Policy)	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Discontinued Operations, Policy	Discontinued Operations The Company classifies assets and liabilities as held for sale when management, having the authority to approve the action, commits to a plan to sell the disposal group, the sale is probable to occur within one year, and the disposal group is available for immediate sale in its present condition. The Company also considers whether an active program to locate a buyer has been initiated, whether the disposal group is marketed actively for sale at a price that is reasonable in relation to its current fair value, and whether actions required to complete the plan indicate it is unlikely significant changes to the plan will be made or the plan will be withdrawn. An asset or business that meets the criteria for held for sale classification is reported as discontinued operations when the disposal represents a strategic shift that has had or will have a major effect on the Company’s operating results. Assets and liabilities of discontinued operations are presented separately in the Consolidated Balance Sheets for current and prior periods commencing in the period in which the asset or business meets all of the held for sale criteria described above. Net income from discontinued operations, net of tax, are separately reported in the Consolidated Statements of Income for current and prior periods commencing in the period in which the asset or business meets all of the held for sale criteria described above, including any gain or loss recognized on the sale or adjustment of the carrying amount to fair value less cost to sell. Certain activity of TIH impacting the Company's footnote disclosures have been removed or revised. The footnote disclosures included herein are presented on a continuing operations basis, unless otherwise noted. Refer to “Note 2. Discontinued Operations” for additional information.
Segment Realignment	Segment Realignment Effective January 1, 2024, several business activities were realigned reflecting updates to the Company’s operating structure. First, the CB&W segment was renamed CSBB and the C&CB segment was renamed WB. Second, the Wealth business was realigned into the WB segment from the CSBB segment, representing a separate reporting unit in that segment. Third, the small business banking client segmentation was realigned into the CSBB segment from the WB segment. Further, TIH was the principal legal entity of the IH segment. As the operations of TIH are now included in discontinued operations, the Company no longer presents the IH segment as one of its reportable segments. The segment disclosures have been revised to reflect the new structure. Refer to “Note 18. Operating Segments” for additional information.
Reclassifications	Reclassifications In addition to the reclassifications discussed above in the Consolidated Balance Sheets, Consolidated Statements of Income, and certain footnotes for discontinued operations and the segment realignment, as applicable, certain other amounts reported in prior periods’ consolidated financial statements have been reclassified to conform to the current presentation.
Use of Estimates in the Preparation of Financial Statements	Use of Estimates in the Preparation of Financial Statements 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 and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates. Material estimates that are particularly susceptible to significant change include the determination of the ACL; determination of fair value for securities, MSRs, LHFS, trading loans, and derivative assets and liabilities; goodwill and other intangible assets; income taxes; and pension and postretirement benefit obligations.