v3.26.1
Fair Value Measurements (Details) - EBP 333 - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments, at fair value $ 6,158,117 $ 5,483,306
Mutual funds    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments, at fair value 212,232 204,410
Quest Diagnostics common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments, at fair value 310,165 295,103
Other common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments, at fair value 287,320 282,820
Total    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments, at fair value 809,717 782,333
Level 1    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments, at fair value 809,717 782,256
Level 1 | Mutual funds    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments, at fair value 212,232 204,410
Level 1 | Quest Diagnostics common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments, at fair value 310,165 295,103
Level 1 | Other common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments, at fair value 287,320 282,743
Level 2    
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 2 | Quest Diagnostics common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments, at fair value 0 0
Level 2 | Other common stock    
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 77
Level 3 | Mutual funds    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments, at fair value 0 0
Level 3 | Quest Diagnostics common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments, at fair value 0 0
Level 3 | Other common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments, at fair value 0 77
NAV    
EBP, Investment, Fair Value and NAV [Line Items]    
Total investments, at fair value $ 5,348,400 $ 4,700,973