v3.26.1
Segment Information - Summary of Operating Segments (Detail) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Disclosure of operating segments [line items]      
Sales revenues ¥ 50,684,952 ¥ 48,036,704 ¥ 45,095,325
Operating expenses 46,918,736 43,241,118 39,742,390
Operating income 3,766,216 4,795,586 5,352,934
Total assets 105,522,331 93,601,350 90,114,296
Investments accounted for using the equity method 5,342,548 5,798,051 5,710,106
Depreciation and amortization 2,392,519 2,251,233 2,087,066
Capital expenditures 6,059,779 5,991,268 4,848,042
Automotive [Member]      
Disclosure of operating segments [line items]      
Sales revenues 45,417,703 43,199,865 41,266,204
Operating expenses 42,640,654 39,259,587 36,644,729
Operating income 2,777,049 3,940,278 4,621,475
Total assets 33,182,372 30,117,987 29,351,344
Investments accounted for using the equity method 4,763,577 5,201,784 5,114,364
Depreciation and amortization 1,417,242 1,378,107 1,268,479
Capital expenditures 2,453,641 2,193,872 2,011,361
Financial services [Member]      
Disclosure of operating segments [line items]      
Sales revenues 4,857,115 4,481,180 3,484,198
Operating expenses 4,005,394 3,797,661 2,914,175
Operating income 851,722 683,519 570,023
Total assets 53,741,709 46,770,786 43,834,183
Investments accounted for using the equity method 124,393 112,640 110,308
Depreciation and amortization 920,432 838,167 784,013
Capital expenditures 3,511,937 3,687,890 2,763,931
All other [Member]      
Disclosure of operating segments [line items]      
Sales revenues 1,651,412 1,447,114 1,368,164
Operating expenses 1,519,333 1,265,920 1,192,923
Operating income 132,079 181,194 175,241
Total assets 4,066,133 2,884,421 3,011,363
Investments accounted for using the equity method 304,242 309,121 282,888
Depreciation and amortization 54,846 34,958 34,574
Capital expenditures 64,749 100,941 103,242
Inter-segment Elimination/Unallocated Amount [Member]      
Disclosure of operating segments [line items]      
Sales revenues (1,241,278) (1,091,455) (1,023,242)
Operating expenses (1,246,644) (1,082,050) (1,009,437)
Operating income 5,366 (9,405) (13,805)
Total assets 14,532,118 13,828,157 13,917,406
Investments accounted for using the equity method 150,336 174,505 202,546
Capital expenditures 29,452 8,565 (30,492)
Revenues from external customers [Member]      
Disclosure of operating segments [line items]      
Sales revenues 50,684,952 48,036,704 45,095,325
Revenues from external customers [Member] | Automotive [Member]      
Disclosure of operating segments [line items]      
Sales revenues 45,201,924 42,996,299 41,080,731
Revenues from external customers [Member] | Financial services [Member]      
Disclosure of operating segments [line items]      
Sales revenues 4,819,003 4,437,827 3,447,195
Revenues from external customers [Member] | All other [Member]      
Disclosure of operating segments [line items]      
Sales revenues 664,026 602,578 567,399
Inter-segment revenues and transfers [Member] | Automotive [Member]      
Disclosure of operating segments [line items]      
Sales revenues 215,779 203,566 185,473
Inter-segment revenues and transfers [Member] | Financial services [Member]      
Disclosure of operating segments [line items]      
Sales revenues 38,112 43,353 37,003
Inter-segment revenues and transfers [Member] | All other [Member]      
Disclosure of operating segments [line items]      
Sales revenues 987,387 844,536 800,766
Inter-segment revenues and transfers [Member] | Inter-segment Elimination/Unallocated Amount [Member]      
Disclosure of operating segments [line items]      
Sales revenues ¥ (1,241,278) ¥ (1,091,455) ¥ (1,023,242)