v3.26.1
Fair value measurement - Information about Changes in Fair Value of Level 3 Assets (Detail) - Available-for-Sale Debt Securities - INR (₨)
₨ in Millions
12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Beginning balance ₨ 149,197.5 ₨ 160,865.0
Total gains or losses (realized/unrealized) — Included in net income 12,882.0 5,864.3
Total gains or losses (realized/unrealized) — Included in other comprehensive income (625.2) 1,351.8
Purchases/additions 80,097.8 65,272.1
Sales (6,164.5) (546.6)
Issuances 0.0 0.0
Settlements (67,372.2) (83,818.7)
Transfers into Level 3 37,600.3 209.6
Transfers out of Level 3 (650.2) 0.0
Foreign currency translation adjustment 0.0 0.0
Ending Balance 204,965.5 149,197.5
Total amount of gains/ (losses) included in net income attributable to change in unrealized gains/ (losses) relating to assets still held at reporting date 13,893.9 5,830.7
Change in unrealized gains/ (losses) for the period included in other comprehensive income for assets held at the end of the reporting period ₨ (621.8) ₨ 433.0