v3.26.1
Income Taxes - Narrative (Details) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2027
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]        
Adjustments for current tax of prior periods   ¥ 15,682 ¥ 4,654 ¥ 4,952
Current tax expense (income), related to Pillar Two income taxes   2,376 317  
Deferred tax expense (income) relating to origination and reversal of temporary differences   ¥ (8,292) ¥ (19,542) ¥ (32,290)
Applicable tax rate 31.50% 30.60% 30.60% 30.60%
Tax effect of tax contingencies in determining taxable profit (loss)   ¥ (1,309) ¥ 426 ¥ (83,784)
Deferred tax expense (income)   (101,034) (71,116) (198,755)
Current and deferred tax relating to items credited (charged) directly to equity   (382) 1,347  
Temporary differences associated with investments in subsidiaries, branches and associates and interests in joint arrangements for which deferred tax assets have not been recognised   86,107 447,645  
Temporary differences associated with investments in subsidiaries, branches and associates and interests in joint arrangements for which deferred tax liabilities have not been recognised   2,163,931 ¥ 578,601  
AMITIZA Antitrust Litigation        
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]        
Deferred tax expense (income)   ¥ (58,393)    
AbbVie break fee case with IRA        
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]        
Tax effect of tax contingencies in determining taxable profit (loss)       ¥ (63,547)