v3.26.1
Intangible Assets - Summary of Changes in Intangible Assets and Goodwill (Detail)
₨ in Millions, $ in Millions
 12 Months Ended
Mar. 31, 2026
INR (₨)
Mar. 31, 2026
USD ($)
Mar. 31, 2025
INR (₨)
Mar. 31, 2024
INR (₨)
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill ₨ 36,217   ₨ 37,883  
Charge for the year 1,877 $ 20 1,632 ₨ 1,485
Impairment for the year 812 9    
Ending Balance of Intangible assets and goodwill 41,086 438 36,217 37,883
Cost        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 45,880   45,840 45,004
Additions during the year 257   110 836
Assets held for sale     (29)  
Acquisition through business combination 7,125      
Exchange differences 555      
Disposals and adjustments during the year (145)   (41)  
Capitalised during the year 0   0 0
Ending Balance of Intangible assets and goodwill 53,672   45,880 45,840
Accumulated amortisation        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 9,663   7,957 6,409
Assets held for sale     20  
Charge for the year 1,877   1,632 1,485
Impairment for the year 972      
Disposals and adjustments during the year (32)      
Capitalised during the year 106   94 63
Ending Balance of Intangible assets and goodwill 12,586   9,663 7,957
Computer software        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 424   540  
Ending Balance of Intangible assets and goodwill 1,002 11 424 540
Computer software | Cost        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 932   926 622
Additions during the year 257   0 180
Assets held for sale     (29)  
Acquisition through business combination 589      
Exchange differences 8      
Disposals and adjustments during the year (46)   (41)  
Capitalised during the year 7   76 124
Ending Balance of Intangible assets and goodwill 1,747   932 926
Computer software | Accumulated amortisation        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 508   386 250
Assets held for sale     20  
Charge for the year 163   48 136
Disposals and adjustments during the year (32)      
Capitalised during the year 106   94  
Ending Balance of Intangible assets and goodwill 745   508 386
Customer contracts        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 23,611   25,027  
Ending Balance of Intangible assets and goodwill 22,196 237 23,611 25,027
Customer contracts | Cost        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 32,592   32,592 32,592
Additions during the year 0      
Acquisition through business combination 0      
Ending Balance of Intangible assets and goodwill 32,592   32,592 32,592
Customer contracts | Accumulated amortisation        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 8,981   7,565 6,154
Charge for the year 1,415   1,416 1,348
Capitalised during the year       63
Ending Balance of Intangible assets and goodwill 10,396   8,981 7,565
Customer relationship        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Ending Balance of Intangible assets and goodwill 927 10    
Customer relationship | Cost        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Acquisition through business combination 1,005      
Exchange differences 76      
Ending Balance of Intangible assets and goodwill 1,081      
Customer relationship | Accumulated amortisation        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Charge for the year 154      
Ending Balance of Intangible assets and goodwill 154      
Development rights        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 30   30  
Ending Balance of Intangible assets and goodwill 29 0 30 30
Development rights | Cost        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 36   36 36
Ending Balance of Intangible assets and goodwill 36   36 36
Development rights | Accumulated amortisation        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 6   6 5
Charge for the year 1   0 1
Ending Balance of Intangible assets and goodwill 7   6 6
Other Intangible assets        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 6   7  
Ending Balance of Intangible assets and goodwill 6 0 6 7
Other Intangible assets | Cost        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 7   7 7
Ending Balance of Intangible assets and goodwill 7   7 7
Other Intangible assets | Accumulated amortisation        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 1   0 0
Charge for the year     1 0
Ending Balance of Intangible assets and goodwill 1   1 0
Carbon credit rights        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 459   626  
Ending Balance of Intangible assets and goodwill 155 2 459 626
Carbon credit rights | Cost        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 626   626  
Additions during the year       626
Ending Balance of Intangible assets and goodwill 626   626 626
Carbon credit rights | Accumulated amortisation        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 167      
Charge for the year 144   167  
Impairment for the year 160      
Ending Balance of Intangible assets and goodwill 471   167  
Goodwill        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 11,596   11,596  
Ending Balance of Intangible assets and goodwill 16,749 179 11,596 11,596
Goodwill | Cost        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 11,596   11,596 11,596
Acquisition through business combination 5,531      
Exchange differences 471      
Disposals and adjustments during the year (37)      
Ending Balance of Intangible assets and goodwill 17,561   11,596 11,596
Goodwill | Accumulated amortisation        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Impairment for the year 812      
Ending Balance of Intangible assets and goodwill 812      
Intangible asset under development        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 91   57  
Ending Balance of Intangible assets and goodwill 22 $ 0 91 57
Intangible asset under development | Cost        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 91   57 151
Additions during the year     110 30
Disposals and adjustments during the year (62)      
Capitalised during the year (7)   (76) (124)
Ending Balance of Intangible assets and goodwill 22   91 57
Intangible asset under development | Accumulated amortisation        
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]        
Beginning Balance of Intangible assets and goodwill 0   0 0
Charge for the year     0 0
Ending Balance of Intangible assets and goodwill ₨ 0   ₨ 0 ₨ 0