v3.26.1
Schedule I Condensed Financial Information - Condensed Statements of Cash Flows (Details) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Condensed Financial Statements, Captions [Line Items]      
Net cash provided by (used in) operating activities ¥ 375,297 ¥ 155,849 ¥ 49,975
Cash flows from (used in) investing activities      
Purchases of securities (779,962) (463,314) (437,408)
Proceeds from sales/redemption of securities 189,284 177,885 189,836
Purchases of intangible assets (17,823) (17,264) (17,911)
Other (2,302) (5,343) (3,316)
Net cash used in investing activities (628,827) (319,977) (273,383)
Cash flows from (used in) financing activities      
Repayments of lease liabilities (2,744) (2,820) (2,409)
Net cash provided by (used in) financing activities 246,752 (210,325) 107,930
Effect of exchange rate changes on cash and cash equivalents 50 (59) 488
Decrease in cash and cash equivalents (6,728) (374,512) (114,990)
Cash and cash equivalents at the beginning of the year 369,811 744,323 859,313
Cash and cash equivalents at the end of the year 363,083 369,811 744,323
Parent Company [Member]      
Condensed Financial Statements, Captions [Line Items]      
Net cash provided by (used in) operating activities 140,554 (133,687) (254,620)
Cash flows from (used in) investing activities      
Purchases of securities (43,943) (21,555) (14,394)
Proceeds from sales/redemption of securities 14,400    
Purchases of intangible assets (8,101) (8,360) (9,235)
Purchases of shares of subsidiaries and associates (11,655) (8,543) (6,596)
Payments into term deposits   (1,861) (1,740)
Other (2,181) (3,641) (588)
Net cash used in investing activities (51,480) (43,960) (32,553)
Cash flows from (used in) financing activities      
Repayments of lease liabilities (1,531) (1,075) (714)
Proceeds from issuance of new shares 217,522    
Payment for the purchase of the equity interest of subsidiaries, through transactions under common control (130,185)    
Net cash provided by (used in) financing activities 85,806 (1,075) (714)
Effect of exchange rate changes on cash and cash equivalents (12)    
Decrease in cash and cash equivalents 174,868 (178,722) (287,887)
Cash and cash equivalents at the beginning of the year 133,350 312,072 599,959
Cash and cash equivalents at the end of the year ¥ 308,218 ¥ 133,350 ¥ 312,072