XML 69 R53.htm IDEA: XBRL DOCUMENT
v3.20.4

Resale and Repurchase Agreements (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2020
Offsetting [Abstract] |
Offsetting, Resale and Repurchase Agreements [Table Text Block] |
|  |  |  | Gross Amounts Not Offset in the Balance Sheet |
(In thousands) | Gross Amount Recognized | Gross Amounts Offset in the Balance Sheet | Net Amounts Presented in the Balance Sheet | Financial Instruments Available for Offset | Securities Collateral Received/Pledged | Net Amount
December 31, 2020 |  |  |  |  |  |
Total resale agreements, subject to master netting arrangements | $ | 1,050,000 |  | $ | (200,000) |  | $ | 850,000 |  | $ | — |  | $ | (850,000) |  | $ | — |
Total repurchase agreements, subject to master netting arrangements | 2,256,113 |  | (200,000) |  | 2,056,113 |  | — |  | (2,056,113) |  | — |
December 31, 2019 |  |  |  |  |  |
Total resale agreements, subject to master netting arrangements | $ | 1,050,000 |  | $ | (200,000) |  | $ | 850,000 |  | $ | — |  | $ | (850,000) |  | $ | — |
Total repurchase agreements, subject to master netting arrangements | 2,030,737 |  | (200,000) |  | 1,830,737 |  | — |  | (1,830,737) |  | — |
Schedule of Underlying Assets of Repurchase Agreements [Table Text Block] | The table below shows the remaining contractual maturities of repurchase agreements outstanding at December 31, 2020 and 2019, in addition to the various types of marketable securities that have been pledged by the Company as collateral for these borrowings.
| Remaining Contractual Maturity of the Agreements |
(In thousands) | Overnight and continuous | Up to 90 days | Greater than 90 days | Total
December 31, 2020 |  |  |  |
Repurchase agreements, secured by: |  |  |  |
U.S. government and federal agency obligations | $ | 150,305 |  | $ | — |  | $ | — |  | $ | 150,305 |
Agency mortgage-backed securities | 1,598,614 |  | 34,018 |  | 220,849 |  | 1,853,481 |
Non-agency mortgage-backed securities | 62,742 |  | — |  | — |  | 62,742 |
Asset-backed securities | 155,917 |  | — |  | — |  | 155,917 |
Other debt securities | 33,668 |  | — |  | — |  | 33,668 |
Total repurchase agreements, gross amount recognized | $ | 2,001,246 |  | $ | 34,018 |  | $ | 220,849 |  | $ | 2,256,113 |
December 31, 2019 |  |  |  |
Repurchase agreements, secured by: |  |  |  |
U.S. government and federal agency obligations | $ | 526,283 |  | $ | — |  | $ | — |  | $ | 526,283 |
Government-sponsored enterprise obligations | 32,575 |  | — |  | — |  | 32,575 |
Agency mortgage-backed securities | 973,774 |  | 48,517 |  | 227,802 |  | 1,250,093 |
Non-agency mortgage-backed securities | 71,399 |  | — |  | — |  | 71,399 |
Asset-backed securities | 60,012 |  | 40,000 |  | — |  | 100,012 |
Other debt securities | 50,375 |  | — |  | — |  | 50,375 |
Total repurchase agreements, gross amount recognized | $ | 1,714,418 |  | $ | 88,517 |  | $ | 227,802 |  | $ | 2,030,737 |

X
- Definition [Table Text Block] for Offsetting, Resale and Repurchase Agreements [Table] + References No definition available. + Details
Name: | cbsh_OffsettingResaleandRepurchaseAgreementsTableTextBlock
Namespace Prefix: | cbsh_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure, as of the most recent balance sheet date, of securities or other assets sold under repurchase agreements. Disclosure may include the following: the type of securities or assets sold under agreements to repurchase, the carrying amount, market value (including accrued interest plus any cash or other assets on deposit. The information is segregated into securities maturing (1) overnight; (2) term up to 90 days; (3) term over 90 days. + References No definition available. + Details
Name: | cbsh_ScheduleofUnderlyingAssetsofRepurchaseAgreementsTableTextBlock
Namespace Prefix: | cbsh_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_OffsettingAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration