v3.26.1
Insurance contracts in the financial services business - Summary of Changes in insurance contract liabilities from insurance contracts not measured under the PAA by measurement component (Detail) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Changes that relate to future service    
Effect of contracts initially recognized during the period   ¥ 1,768
Total changes that relate to future service   101,865
Changes that relate to current service    
Total changes that relate to current service   (151,025)
Insurance finance expenses (income)   30,155
Cash flows    
Other   (1,334)
Estimates of present value of future cash flows [member]    
Changes that relate to future service    
Effect of contracts initially recognized during the period   2,391,895
Risk adjustment for non-financial risk [member]    
Changes that relate to future service    
Effect of contracts initially recognized during the period   44,335
CSM [member]    
Changes that relate to future service    
Effect of contracts initially recognized during the period   389,234
Insurance contracts not measured under PAA [member]    
Disclosure of reconciliation of changes in insurance contracts by components [line items]    
Insurance contract assets, Beginning ¥ (47,715) (56,975)
Insurance contract liabilities, Beginning 12,745,304 12,986,833
Net amounts, Beginning 12,697,589 12,929,858
Changes that relate to future service    
Changes in estimates that do not adjust the CSM 9,477 12,508
Effect of contracts initially recognized during the period 1,474 1,768
Total changes that relate to future service 10,951 14,276
Changes that relate to current service    
CSM recognized in profit or loss for the services provided (79,908) (151,025)
Change in risk adjustment for non-financial risk due to release of risk (16,164) (28,681)
Experience adjustments (7,549) 656
Total changes that relate to current service (103,621) (179,050)
Changes that relate to past service   0
Insurance service result (92,351) (164,774)
Insurance finance expenses (income) (141,603) (633,829)
Total amounts recognized in comprehensive income (233,954) (798,603)
Cash flows    
Premiums received 893,895 1,894,792
Insurance acquisition cash flows (77,407) (151,614)
Claims and other insurance service expenses paid (520,614) (1,179,036)
Total cash flows 295,874 564,142
Other (14,090) 2,192
Impact from loss of control of the Financial Services business (12,745,419)  
Insurance contract assets, Ending   (47,715)
Insurance contracts liabilities, Ending   12,745,304
Net amounts, Ending   12,697,589
Insurance contracts not measured under PAA [member] | Estimates of present value of future cash flows [member]    
Disclosure of reconciliation of changes in insurance contracts by components [line items]    
Insurance contract assets, Beginning (245,602) (291,878)
Insurance contract liabilities, Beginning 10,413,511 10,697,166
Net amounts, Beginning 10,167,909 10,405,288
Changes that relate to future service    
Changes in estimates that adjust the CSM 14,984 276,707
Changes in estimates that do not adjust the CSM 6,908 11,762
Effect of contracts initially recognized during the period (177,699) (431,801)
Total changes that relate to future service (155,807) (143,332)
Changes that relate to current service    
Experience adjustments (7,549) 656
Total changes that relate to current service (7,549) 656
Changes that relate to past service 324 6
Insurance service result (163,032) (142,670)
Insurance finance expenses (income) (152,695) (661,734)
Total amounts recognized in comprehensive income (315,727) (804,404)
Cash flows    
Premiums received 893,895 1,894,792
Insurance acquisition cash flows (77,407) (151,614)
Claims and other insurance service expenses paid (520,614) (1,179,036)
Total cash flows 295,874 564,142
Other (12,883) 2,883
Impact from loss of control of the Financial Services business (10,135,173)  
Insurance contract assets, Ending   (245,602)
Insurance contracts liabilities, Ending   10,413,511
Net amounts, Ending   10,167,909
Insurance contracts not measured under PAA [member] | Risk adjustment for non-financial risk [member]    
Disclosure of reconciliation of changes in insurance contracts by components [line items]    
Insurance contract assets, Beginning 24,501 27,824
Insurance contract liabilities, Beginning 417,430 388,658
Net amounts, Beginning 441,931 416,482
Changes that relate to future service    
Changes in estimates that adjust the CSM 47,569 10,662
Changes in estimates that do not adjust the CSM 2,569 746
Effect of contracts initially recognized during the period 21,537 44,335
Total changes that relate to future service 71,675 55,743
Changes that relate to current service    
Change in risk adjustment for non-financial risk due to release of risk (16,164) (28,681)
Total changes that relate to current service (16,164) (28,681)
Changes that relate to past service (5) (6)
Insurance service result 55,506 27,056
Insurance finance expenses (income) (1,373) (2,250)
Total amounts recognized in comprehensive income 54,133 24,806
Cash flows    
Other 0 643
Impact from loss of control of the Financial Services business (496,064)  
Insurance contract assets, Ending   24,501
Insurance contracts liabilities, Ending   417,430
Net amounts, Ending   441,931
Insurance contracts not measured under PAA [member] | CSM [member]    
Disclosure of reconciliation of changes in insurance contracts by components [line items]    
Insurance contract assets, Beginning 173,386 207,079
Insurance contract liabilities, Beginning 1,914,363 1,901,009
Net amounts, Beginning 2,087,749 2,108,088
Changes that relate to future service    
Changes in estimates that adjust the CSM (62,553) (287,369)
Effect of contracts initially recognized during the period 157,636 389,234
Total changes that relate to future service 95,083 101,865
Changes that relate to current service    
CSM recognized in profit or loss for the services provided (79,908) (151,025)
Total changes that relate to current service (79,908) (151,025)
Insurance service result 15,175 (49,160)
Insurance finance expenses (income) 12,465 30,155
Total amounts recognized in comprehensive income 27,640 (19,005)
Cash flows    
Other (1,207) (1,334)
Impact from loss of control of the Financial Services business ¥ (2,114,182)  
Insurance contract assets, Ending   173,386
Insurance contracts liabilities, Ending   1,914,363
Net amounts, Ending   ¥ 2,087,749