v3.26.1
Other equity - Summary of Foreign Currency Translation Reserve (Detail)
₨ in Millions, $ in Millions
12 Months Ended
Mar. 31, 2026
INR (₨)
Mar. 31, 2026
USD ($)
Mar. 31, 2025
INR (₨)
Mar. 31, 2024
INR (₨)
Disclosure Of Detailed Information About Reserve Of Exchange Differences On Translation Of Equity [Line Items]        
Beginning balance ₨ 131,112   ₨ 121,697 ₨ 118,400
(Gain) recycled to profit & loss (refer Note 29) (428) $ (5)    
Ending balance 144,396 1,538 131,112 121,697
Reserve of exchange differences on translation        
Disclosure Of Detailed Information About Reserve Of Exchange Differences On Translation Of Equity [Line Items]        
Beginning balance 565   474 547
Exchange differences on translation of foreign operations (Net) (1,069)   87 (68)
Allocation to non controlling interest (149)   4 (5)
(Gain) recycled to profit & loss (refer Note 29) (428)      
Ending balance ₨ (1,081) $ (12) ₨ 565 ₨ 474