v3.26.1
Share-Based Compensation (SARs Activity) (Details) - Hindalco SARs [Member]
$ / shares in Units, $ in Millions
12 Months Ended
Mar. 31, 2026
USD ($)
$ / shares
shares
Mar. 31, 2026
USD ($)
₨ / shares
shares
Mar. 31, 2025
USD ($)
shares
Mar. 31, 2025
₨ / shares
Mar. 31, 2024
USD ($)
shares
Mar. 31, 2024
₨ / shares
Mar. 31, 2026
₨ / shares
Aggregate Intrinsic Value              
Total share-based liabilities paid | $ $ 12   $ 12   $ 5    
SARs [Member]              
Number of SARs              
Outstanding, beginning of period (shares) | shares 4,914,602            
Granted (shares) | shares 1,685,232   1,451,753   2,620,019    
Exercised (shares) | shares (2,611,517)            
Forfeited/Cancelled (shares) | shares (308,039)            
Outstanding, end of period (shares) | shares 3,680,278   4,914,602        
Number of Shares, Exercisable | shares 548,207 548,207          
Weighted Average Exercise Price              
Outstanding, beginning of period (Indian Rupees/USD per share) | ₨ / shares   ₨ 490.07          
Granted (Indian Rupees/USD per share) | ₨ / shares   635.78   ₨ 684.10   ₨ 417.90  
Exercised (Indian Rupees/USD per share) | ₨ / shares   427.18          
Forfeited/Cancelled (Indian Rupees/USD per share) | ₨ / shares   608.57          
Outstanding, end of period (Indian Rupees/USD per share) | ₨ / shares   ₨ 591.49   ₨ 490.07      
Weighted Average Exercise Price (Indian Rupees/USD per share), Exercisable | ₨ / shares             ₨ 556.47
Weighted Average Remaining Contractual Term              
Weighted Average Remaining Contractual Term, Outstanding 5 years 4 months 24 days   5 years 2 months 12 days        
Weighted Average Remaining Contractual Term, Granted 6 years 3 months 18 days            
Weighted Average Remaining Contractual Term, Outstanding 5 years 4 months 24 days   5 years 2 months 12 days        
Weighted Average Remaining Contractual Term, Exercisable 4 years 4 months 24 days            
Aggregate Intrinsic Value              
Aggregate Intrinsic Value, Outstanding | $ $ 12            
Aggregate Intrinsic Value, Granted | $ 4            
Aggregate Intrinsic Value, Exercised | $ $ 12   $ 12   $ 5    
Aggregate Intrinsic Value, Forfeited/Cancelled | $ / shares $ 0            
Aggregate Intrinsic Value, Outstanding | $ $ 12   $ 12        
Aggregate Intrinsic Value, Exercisable | $ $ 2 ₨ 2          
SARs [Member] | Minimum              
Aggregate Intrinsic Value              
Risk-free interest rate 6.23%   6.61%   6.95%    
Volatility 28.00%   29.00%   26.00%