v3.25.2
Insurance contracts in the financial services segment - Summary of the Remaining Undiscounted Net Cash Flows (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2025
Mar. 31, 2024
Disclosure Of Remaining Undiscounted Cash Flows From Insurance Contracts Liabilities And Marketable Securities And Security Investments [Line Items]    
Insurance contract liabilities and investment contract liabilities ¥ 22,740,658 ¥ 19,173,131
Securities held in the insurance business 20,876,179 20,808,629
Indefinite Term [Member]    
Disclosure Of Remaining Undiscounted Cash Flows From Insurance Contracts Liabilities And Marketable Securities And Security Investments [Line Items]    
Securities held in the insurance business 4,372,358 3,687,375
Not later than one year [member]    
Disclosure Of Remaining Undiscounted Cash Flows From Insurance Contracts Liabilities And Marketable Securities And Security Investments [Line Items]    
Insurance contract liabilities and investment contract liabilities 64,000 60,673
Securities held in the insurance business 699,185 780,798
Later than one year and not later than two years [member]    
Disclosure Of Remaining Undiscounted Cash Flows From Insurance Contracts Liabilities And Marketable Securities And Security Investments [Line Items]    
Insurance contract liabilities and investment contract liabilities 95,151 86,008
Securities held in the insurance business 358,761 341,277
Later than two years and not later than three years [member]    
Disclosure Of Remaining Undiscounted Cash Flows From Insurance Contracts Liabilities And Marketable Securities And Security Investments [Line Items]    
Insurance contract liabilities and investment contract liabilities 157,008 127,079
Securities held in the insurance business 398,222 355,062
Later than three years and not later than four years [member]    
Disclosure Of Remaining Undiscounted Cash Flows From Insurance Contracts Liabilities And Marketable Securities And Security Investments [Line Items]    
Insurance contract liabilities and investment contract liabilities 246,745 175,412
Securities held in the insurance business 314,310 374,354
Later than four years and not later than five years [member]    
Disclosure Of Remaining Undiscounted Cash Flows From Insurance Contracts Liabilities And Marketable Securities And Security Investments [Line Items]    
Insurance contract liabilities and investment contract liabilities 288,630 248,021
Securities held in the insurance business 283,300 305,612
Later than five years [member]    
Disclosure Of Remaining Undiscounted Cash Flows From Insurance Contracts Liabilities And Marketable Securities And Security Investments [Line Items]    
Insurance contract liabilities and investment contract liabilities 21,889,124 18,475,938
Securities held in the insurance business ¥ 14,450,043 ¥ 14,964,151