v3.26.1
Accumulated other comprehensive income - Changes in Accumulated Other Comprehensive Income After Tax (Detail)
₨ in Millions, $ in Millions
 12 Months Ended
Mar. 31, 2026
INR (₨)
Mar. 31, 2026
USD ($)
Mar. 31, 2025
INR (₨)
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Balance ₨ 8,622,891.0   ₨ 7,886,182.8
Net unrealized gain/ (loss) arising during the period (282,997.9)   147,594.0
Past Service cost recognised due to plan amendment (7,366.8)    
Amounts reclassified to income (42,535.5)   9,835.5
Amortization of past service cost 842.9    
Long-duration insurance contract discount rate change 184,210.0   (59,827.6)
Transferred to undistributed policyholders earnings account (13,502.5)   16,525.9
Less: Other comprehensive income attributable to shareholders of noncontrolling interest (1,725.2)   1,393.3
Balance 9,160,694.7 $ 97,630.9 8,622,891.0
AFS debt Securities      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Balance 87,780.0   (7,505.2)
Net unrealized gain/ (loss) arising during the period (291,560.2)   145,589.7
Past Service cost recognised due to plan amendment 0.0    
Amounts reclassified to income (42,535.5)   9,835.5
Amortization of past service cost 0.0    
Long-duration insurance contract discount rate change 0.0   0.0
Transferred to undistributed policyholders earnings account 169,910.0   (58,778.7)
Less: Other comprehensive income attributable to shareholders of noncontrolling interest (1,763.9)   1,361.3
Balance (74,641.8) (795.5) 87,780.0
Foreign Currency Translation Reserve      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Balance 9,414.1   7,441.8
Net unrealized gain/ (loss) arising during the period 8,562.3   2,004.3
Past Service cost recognised due to plan amendment 0.0    
Amounts reclassified to income 0.0   0.0
Amortization of past service cost 0.0    
Long-duration insurance contract discount rate change 0.0   0.0
Transferred to undistributed policyholders earnings account 0.0   0.0
Less: Other comprehensive income attributable to shareholders of noncontrolling interest 125.1   32.0
Balance 17,851.3 190.3 9,414.1
Past Service Cost [Member]      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Balance 0.0    
Net unrealized gain/ (loss) arising during the period 0.0    
Past Service cost recognised due to plan amendment (7,366.8)    
Amounts reclassified to income 0.0    
Amortization of past service cost 842.9    
Long-duration insurance contract discount rate change 0.0    
Transferred to undistributed policyholders earnings account 797.5    
Less: Other comprehensive income attributable to shareholders of noncontrolling interest (86.4)    
Balance (5,640.0) (60.1) 0.0
Long-Duration Insurance Contract      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Balance 0.0   (15,477.0)
Net unrealized gain/ (loss) arising during the period 0.0   0.0
Past Service cost recognised due to plan amendment 0.0    
Amounts reclassified to income 0.0   0.0
Amortization of past service cost 0.0    
Long-duration insurance contract discount rate change 184,210.0   (59,827.6)
Transferred to undistributed policyholders earnings account (184,210.0)   75,304.6
Less: Other comprehensive income attributable to shareholders of noncontrolling interest 0.0   0.0
Balance 0.0 0.0 0.0
Accumulated Other Comprehensive Income (Loss)      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Balance 97,194.1   (15,540.4)
Balance ₨ (62,430.5) $ (665.4) ₨ 97,194.1