v3.25.2
Summary of Significant Accounting Policies - Schedule of Intangible Assets And Basis Of Amortization (Detail)
 12 Months Ended
Mar. 31, 2025
Investment Management Contract [Member]  
Schedule Of Intangible Assets [Line Items]  
Indefinite Lived Intangible Asset Useful Life Indefinite
Amortization method Not applicable
Value of Business Acquired (VOBA) [Member]  
Schedule Of Intangible Assets [Line Items]  
Finite Lived Intangible Assets Useful Life Life of the underlying contracts
Amortization method Constant level basis [1]
Distribution Network [Member]  
Schedule Of Intangible Assets [Line Items]  
Useful lives (years) 17 years
Amortization method Straight line
Customer Relationship [Member]  
Schedule Of Intangible Assets [Line Items]  
Useful lives (years) 17 years
Amortization method Straight line
Transferable Development Rights [Member]  
Schedule Of Intangible Assets [Line Items]  
Useful lives (years) 8 years
Amortization method Straight line
Brand [Member]  
Schedule Of Intangible Assets [Line Items]  
Indefinite Lived Intangible Asset Useful Life Indefinite
Indefinite Lived Intangible Assets Amortization Method Not applicable
[1] VOBA is amortised on a constant-level basis that approximates straight-line amortization (Refer note 20)