v3.26.1
Employee Benefits - Additional Information (Detail) - INR (₨)
₨ in Millions
12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Disclosure of defined benefit plans [line items]      
Cash settled [1] ₨ 4,465 ₨ 5,542 ₨ 5,590
Total expense of Employee benefits plans 25,565 20,306 19,227
Total expense of provident fund 7,629 3,300 3,038
Provident Fund Obligation [member]      
Disclosure of defined benefit plans [line items]      
Total expense of provident fund 7,058 6,517 6,265
Defined contribution plans [Member]      
Disclosure of defined benefit plans [line items]      
Total expense of Employee benefits plans 11,146 10,584 9,969
Cash Settled RSU [Member]      
Disclosure of defined benefit plans [line items]      
Cash settled ₨ 0 (9) ₨ 6
Actuarial assumption of discount rates [member]      
Disclosure of defined benefit plans [line items]      
Percentage of reasonably possible increase in actuarial assumption 1.00%    
Increase/ (decrease) in gratuity benefit obligation due to reasonably possible increase in actuarial assumption ₨ 2,228 1,807  
Increase/ (decrease) in gratuity benefit obligation due to reasonably possible decrease in actuarial assumption ₨ (1,914) (1,565)  
Actuarial assumption of expected rates of salary increases [member]      
Disclosure of defined benefit plans [line items]      
Percentage of reasonably possible increase in actuarial assumption 1.00%    
Increase/ (decrease) in gratuity benefit obligation due to reasonably possible increase in actuarial assumption ₨ 1,620 1,189  
Increase/ (decrease) in gratuity benefit obligation due to reasonably possible decrease in actuarial assumption ₨ (1,512) ₨ (1,129)  
[1] Includes ₹ 6, ₹ (9) and ₹ Nil for the years ended March 31, 2024, 2025 and 2026, respectively, towards cash settled ADSs and RSUs.