XML 121 R106.htm IDEA: XBRL DOCUMENT v3.8.0.1
Investment in Securities - Additional Information (Detail)
¥ in Millions
12 Months Ended
Mar. 31, 2018
JPY (¥)
Investment
Mar. 31, 2017
JPY (¥)
Investment
Mar. 31, 2016
JPY (¥)
Schedule of Investments [Line Items]      
Net unrealized holding gains (losses) on trading securities ¥ 14,497 ¥ 19,049 ¥ (84,678)
Proceeds from sales of available-for-sale securities 456,270 549,865 464,232
Available-for-sale securities gross realized gains 31,312 33,804 32,593
Available-for-sale securities gross realized losses 596 3,103 467
Write-downs of securities 1,246 6,608 4,515
Aggregate carrying amount of other securities accounted for under the cost method 27,334 25,597  
Aggregate carrying amount of other securities not evaluated for impairment 27,260 25,396  
Investment funds fair value ¥ 37,631 ¥ 24,894  
Number of investment securities in an unrealized loss position | Investment 320 325  
Finance revenues ¥ 15,756 ¥ 14,031 12,712
Carrying amounts of debt securities acquired with evidence of deterioration of credit quality 17 18  
Nominal value of debt securities acquired with evidence of deterioration of credit quality 337 355  
Outstanding balance of accretable yield of debt securities acquired with evidence of deterioration of credit quality 298 402  
CMBS and RMBS in the Americas, and other asset-backed securities      
Schedule of Investments [Line Items]      
Non-credit components of other-than-temporary impairments, gross unrealized gains 42 57 61
Non-credit components of other-than-temporary impairments losses, accumulated other comprehensive income 0 0 4
Non-credit components of other-than-temporary impairments, unrealized gain net of taxes 33 36 39
Non-credit components of other-than-temporary impairments gains, accumulated other comprehensive income 0 0 ¥ 6
Available-for-sale securities      
Schedule of Investments [Line Items]      
Investment funds fair value 22,365 15,400  
Available-for-sale securities | Government Securities      
Schedule of Investments [Line Items]      
Investment funds fair value 719 1,015  
Available-for-sale securities | Foreign Corporate Debt Securities      
Schedule of Investments [Line Items]      
Investment funds fair value 8,882 1,026  
Other securities      
Schedule of Investments [Line Items]      
Investment funds fair value ¥ 5,665 ¥ 7,453