XML 37 R27.htm IDEA: XBRL DOCUMENT
v3.26.1

Legal and Regulatory Proceedings | 3 Months Ended
--- | ---
Mar. 31, 2026
Legal Proceedings [Abstract] |
Legal Matters and Contingencies [Text Block] | Legal and Regulatory Proceedings The Company has various legal proceedings pending at March 31, 2026, arising in the normal course of business. While some matters pending against the Company specify damages claimed by plaintiffs, others do not seek a specified amount of damages or are at early stages of the legal process. The Company records a loss accrual for all legal and regulatory matters for which it deems a loss is probable and can be reasonably estimated. Some matters, which are in the early stages, have not yet progressed to the point where a loss amount can be determined to be probable and estimable.

X
- Definition Legal Proceedings [Abstract] + References No definition available. + Details
Name: | cbsh_LegalProceedingsAbstract
Namespace Prefix: | cbsh_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The entire disclosure for legal proceedings, legal contingencies, litigation, regulatory and environmental matters and other contingencies. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 450 -Name Accounting Standards Codification -Publisher FASB -URI https://asc.fasb.org/450/tableOfContent + Details
Name: | us-gaap_LegalMattersAndContingenciesTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration