v3.26.1
Cover
12 Months Ended
Dec. 31, 2025
Document Information [Line Items]  
Document Type 11-K
Amendment Flag false
Entity Registrant Name NATIONAL GRID PLC
Entity Central Index Key 0001004315
EBP 007 [Member]  
Document Information [Line Items]  
Document Type 11-K
Amendment Flag false
Document Period End Date Dec. 31, 2025
Document Fiscal Year Focus 2025
Document Fiscal Period Focus FY
Entity Registrant Name NATIONAL GRID PLC
Entity Central Index Key 0001004315
Current Fiscal Year End Date --12-31