v3.25.2
Financial Risks - Summary of Non-derivative Financial Liabilities and Derivative Financial Liabilities by a Remaining Contract Maturity Period (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2025
Mar. 31, 2024
Within 1 year [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Total ¥ (17,028,902) ¥ (16,713,284)
Between 1 and 3 years [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Total (15,833,244) (13,357,180)
Between 3 and 5 years [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Total (6,314,963) (6,965,631)
Later than 5 years [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Total (2,694,201) (2,870,280)
Book value [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Total 39,112,760 36,993,969
Contractual cash flows [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Total (41,871,310) (39,906,376)
Derivative financial liabilities [Member] | Within 1 year [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Interest derivative (83,505) (74,298)
In 73,959 150,390
Out (130,116) (222,251)
Total (139,663) (146,158)
Derivative financial liabilities [Member] | Between 1 and 3 years [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Interest derivative (108,063) (103,424)
In 759,648 433,343
Out (840,065) (519,535)
Total (188,480) (189,617)
Derivative financial liabilities [Member] | Between 3 and 5 years [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Interest derivative (22,712) (54,923)
In 66,990 362,638
Out (74,389) (427,529)
Total (30,111) (119,815)
Derivative financial liabilities [Member] | Later than 5 years [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Interest derivative (6,061) (5,040)
In 146,931 181,391
Out (152,181) (200,860)
Total (11,311) (24,508)
Derivative financial liabilities [Member] | Book value [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Interest derivative 196,389 238,503
Out 123,493 193,686
Total 319,881 432,189
Derivative financial liabilities [Member] | Contractual cash flows [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Interest derivative (220,341) (237,685)
In 1,047,528 1,127,763
Out (1,196,751) (1,370,175)
Total (369,564) (480,098)
Non-derivative financial liabilities [Member] | Within 1 year [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Short-term debt (1,565,387) (1,398,947)
Commercial paper (4,012,371) (4,222,660)
Long-term debt (11,209,068) (10,862,374)
Lease liabilities (102,412) (83,145)
Total (16,889,239) (16,567,126)
Non-derivative financial liabilities [Member] | Between 1 and 3 years [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Long-term debt (15,485,265) (13,051,900)
Lease liabilities (159,500) (115,664)
Total (15,644,764) (13,167,564)
Non-derivative financial liabilities [Member] | Between 3 and 5 years [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Long-term debt (6,190,498) (6,770,969)
Lease liabilities (94,354) (74,847)
Total (6,284,852) (6,845,816)
Non-derivative financial liabilities [Member] | Later than 5 years [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Long-term debt (2,409,143) (2,601,665)
Lease liabilities (273,747) (244,107)
Total (2,682,891) (2,845,772)
Non-derivative financial liabilities [Member] | Book value [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Short-term debt 1,552,166 1,387,832
Commercial paper 3,912,303 4,100,127
Long-term debt 32,795,058 30,611,253
Lease liabilities 533,351 462,568
Total 38,792,879 36,561,780
Non-derivative financial liabilities [Member] | Contractual cash flows [Member]    
Disclosure of non-derivative financial liabilities and derivative financial liabilities by a remaining contract maturity period [Line items]    
Short-term debt (1,565,387) (1,398,947)
Commercial paper (4,012,371) (4,222,660)
Long-term debt (35,293,975) (33,286,908)
Lease liabilities (630,013) (517,763)
Total ¥ (41,501,746) ¥ (39,426,278)