v3.25.3
Assets held for sale - Narrative (Details)
£ in Millions, $ in Millions
2 Months Ended 6 Months Ended
Aug. 14, 2025
GBP (£)
May 29, 2025
GBP (£)
May 29, 2025
USD ($)
May 29, 2025
GBP (£)
Sep. 30, 2025
GBP (£)
Sep. 30, 2024
GBP (£)
Disclosure Of Detailed Information About Assets Held For Sale [Line Items]            
Profit (loss)         £ 618 £ 648
National Grid Renewables            
Disclosure Of Detailed Information About Assets Held For Sale [Line Items]            
Profit (loss)       £ (14)   (17)
National Grid Renewables | Assets and liabilities classified as held for sale            
Disclosure Of Detailed Information About Assets Held For Sale [Line Items]            
Consideration received   £ 1,531 $ 2,061      
Grain LNG            
Disclosure Of Detailed Information About Assets Held For Sale [Line Items]            
Profit (loss)         £ 68 £ 69
Grain LNG | Assets and liabilities classified as held for sale | Forecast            
Disclosure Of Detailed Information About Assets Held For Sale [Line Items]            
Consideration received £ 1,660