v3.26.1
Fair Value Measurements - Summary of Fair Value of the Plan's Assets (Detail) - EBP 006 [Member] - USD ($)
Dec. 31, 2025
Dec. 31, 2024
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value $ 1,332,135,586 $ 1,104,311,071
Fair Value, Inputs, Level 1 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 1,331,850,376 1,104,151,951
Fair Value, Inputs, Level 2 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 285,210 159,120
Fair Value, Inputs, Level 3 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 0 0
CIBC common stock [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 61,082,999 44,296,867
CIBC common stock [Member] | Fair Value, Inputs, Level 1 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 61,082,999 44,296,867
CIBC common stock [Member] | Fair Value, Inputs, Level 2 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 0 0
CIBC common stock [Member] | Fair Value, Inputs, Level 3 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 0 0
Short term investment fund [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 285,210 159,120
Short term investment fund [Member] | Fair Value, Inputs, Level 1 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 0 0
Short term investment fund [Member] | Fair Value, Inputs, Level 2 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 285,210 159,120
Short term investment fund [Member] | Fair Value, Inputs, Level 3 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 0 0
Registered investment companies [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 788,012,635 684,496,907
Registered investment companies [Member] | Fair Value, Inputs, Level 1 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 788,012,635 684,496,907
Registered investment companies [Member] | Fair Value, Inputs, Level 2 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 0 0
Registered investment companies [Member] | Fair Value, Inputs, Level 3 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 0 0
Common/collective trusts [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 482,754,742 375,358,177
Common/collective trusts [Member] | Fair Value, Inputs, Level 1 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 482,754,742 375,358,177
Common/collective trusts [Member] | Fair Value, Inputs, Level 2 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value 0 0
Common/collective trusts [Member] | Fair Value, Inputs, Level 3 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value $ 0 $ 0