v3.26.1
DERIVATIVE INSTRUMENTS - INCOME STATEMENT RELATED DISCLOSURES (Details) - Not Designated as Hedging Instrument - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2026
Mar. 31, 2025
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of gain (loss) recognized in income on derivatives $ 59 $ 30,276 $ (1,065) $ 28,483
ES | Physical commodity contracts | Operating revenues        
Derivative Instruments, Gain (Loss) [Line Items]        
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]     Nonutility Nonutility
Amount of gain (loss) recognized in income on derivatives (829) 36,080 $ (1,590) $ 33,448
ES | Physical commodity contracts | Natural gas purchases        
Derivative Instruments, Gain (Loss) [Line Items]        
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]     Natural gas purchases Natural gas purchases
Amount of gain (loss) recognized in income on derivatives 1,403 725 $ 947 $ (1,027)
ES | Physical commodity contracts | Operation and maintenance        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of gain (loss) recognized in income on derivatives 37 (2,179) 33 (1,126)
ES | Financial commodity contracts        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of gain (loss) recognized in income on derivatives (552) (4,350) (455) (2,812)
NJNG        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of gain (loss) recognized in income on derivatives (13,057) 24,850 (17,249) 17,403
NJNG | Physical commodity contracts        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of gain (loss) recognized in income on derivatives (3,331) (5,188) (3,045) (18,574)
NJNG | Financial commodity contracts        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of gain (loss) recognized in income on derivatives $ (9,726) $ 30,038 $ (14,204) $ 35,977