v3.26.1
FAIR VALUE MEASUREMENTS (Details) - EBP 007 - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value $ 152,100 $ 224,800
Total investments at fair value 4,316,111 4,342,550
Total    
EBP, Master Trust [Line Items]    
Total investments at fair value 4,284,394 4,311,912
Total | Common stock of International Paper Company    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 152,139 222,814
Total | Equities    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 3,049,536 3,120,610
Total | Fixed income    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 885,146 750,735
Total | Derivatives    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 899 1,590
Total | Cash and cash equivalents    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 26,938 49,572
Total | Interest bearing cash    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 9,735 17,710
Total | Non-cash    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 3,370 3,632
Total | Self-directed brokerage accounts    
EBP, Master Trust [Line Items]    
Investment, excluding plan interest in master trust, fair value 156,631 145,249
Active Markets for Identical Assets (Level 1)    
EBP, Master Trust [Line Items]    
Total investments at fair value 1,105,501 1,351,424
Active Markets for Identical Assets (Level 1) | Common stock of International Paper Company    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 152,139 222,814
Active Markets for Identical Assets (Level 1) | Equities    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 763,571 919,596
Active Markets for Identical Assets (Level 1) | Fixed income    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 0 0
Active Markets for Identical Assets (Level 1) | Derivatives    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 0 0
Active Markets for Identical Assets (Level 1) | Cash and cash equivalents    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 26,938 49,572
Active Markets for Identical Assets (Level 1) | Interest bearing cash    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 9,735 17,710
Active Markets for Identical Assets (Level 1) | Non-cash    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 0 0
Active Markets for Identical Assets (Level 1) | Self-directed brokerage accounts    
EBP, Master Trust [Line Items]    
Investment, excluding plan interest in master trust, fair value 153,118 141,732
Other Observable Inputs (Level 2)    
EBP, Master Trust [Line Items]    
Total investments at fair value 3,176,263 2,956,638
Other Observable Inputs (Level 2) | Common stock of International Paper Company    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 0 0
Other Observable Inputs (Level 2) | Equities    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 2,285,965 2,201,014
Other Observable Inputs (Level 2) | Fixed income    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 883,415 748,475
Other Observable Inputs (Level 2) | Derivatives    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 0 0
Other Observable Inputs (Level 2) | Cash and cash equivalents    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 0 0
Other Observable Inputs (Level 2) | Interest bearing cash    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 0 0
Other Observable Inputs (Level 2) | Non-cash    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 3,370 3,632
Other Observable Inputs (Level 2) | Self-directed brokerage accounts    
EBP, Master Trust [Line Items]    
Investment, excluding plan interest in master trust, fair value 3,513 3,517
Significant Unobservable Inputs (Level 3)    
EBP, Master Trust [Line Items]    
Total investments at fair value 2,630 3,850
Significant Unobservable Inputs (Level 3) | Common stock of International Paper Company    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 0 0
Significant Unobservable Inputs (Level 3) | Equities    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 0 0
Significant Unobservable Inputs (Level 3) | Fixed income    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 1,731 2,260
Significant Unobservable Inputs (Level 3) | Derivatives    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 899 1,590
Significant Unobservable Inputs (Level 3) | Cash and cash equivalents    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 0 0
Significant Unobservable Inputs (Level 3) | Interest bearing cash    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 0 0
Significant Unobservable Inputs (Level 3) | Non-cash    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value 0 0
Significant Unobservable Inputs (Level 3) | Self-directed brokerage accounts    
EBP, Master Trust [Line Items]    
Investment, excluding plan interest in master trust, fair value 0 0
Investments measured at net asset value | Real Estate Funds    
EBP, Master Trust [Line Items]    
Investment, plan interest in master trust, fair value $ 31,717 $ 30,638
Redemption notice period 30 days 30 days