v3.25.1
Share-Based Compensation (Fair Value Assumptions) (Details) - SARs [Member] - Hindalco SARs [Member]
12 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Mar. 31, 2023
Assumptions used in estimating fair value of SARs      
Dividend yield 0.50% 0.54% 1.03%
Minimum      
Assumptions used in estimating fair value of SARs      
Risk-free interest rate 6.61% 6.95% 3.11%
Volatility 29.00% 26.00% 32.00%
Maximum      
Assumptions used in estimating fair value of SARs      
Risk-free interest rate 6.71% 7.15% 7.24%
Volatility 40.00% 43.00% 47.00%