v3.26.1
Fair Value Measurements (Details) - EBP 002 - USD ($)
Dec. 31, 2025
Dec. 31, 2024
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments at fair value $ 1,540,983,000 $ 1,417,978,486
Fair Value | MillerKnoll, Inc. common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments at fair value 36,017,630 41,279,551
Fair Value | Mutual funds    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments at fair value 215,140,970 281,567,020
Level 1    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments at fair value 251,158,600 322,846,571
Level 1 | MillerKnoll, Inc. common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments at fair value 36,017,630 41,279,551
Level 1 | Mutual funds    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments at fair value 215,140,970 281,567,020
Level 2    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments at fair value 0 0
Level 2 | MillerKnoll, Inc. common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments at fair value 0 0
Level 2 | Mutual funds    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments at fair value 0 0
Level 3    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments at fair value 0 0
Level 3 | MillerKnoll, Inc. common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments at fair value 0 0
Level 3 | Mutual funds    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments at fair value 0 0
NAV | Other investments measured at NAV    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments at fair value $ 1,289,824,400 $ 1,095,131,915