Pension Plans (Fair Value of Pension Plan Assets by Asset Category) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2020		Mar. 31, 2019		Mar. 31, 2018
Japan
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		¥ 122,780		¥ 123,628		¥ 121,269
Japan | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Japan | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		33,076		32,644
Japan | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Japan | Defined Benefit Plan, Equity Securities | Japan Pooled Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		14,434	[1]	19,824	[2]
Japan | Defined Benefit Plan, Equity Securities | Japan Pooled Funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0	[1]	0	[2]
Japan | Defined Benefit Plan, Equity Securities | Japan Pooled Funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0	[1]	0	[2]
Japan | Defined Benefit Plan, Equity Securities | Japan Pooled Funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0	[1]	0	[2]
Japan | Defined Benefit Plan, Equity Securities | Other than Japan Pooled Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[3]	15,207		24,535
Japan | Defined Benefit Plan, Equity Securities | Other than Japan Pooled Funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[3]	0		0
Japan | Defined Benefit Plan, Equity Securities | Other than Japan Pooled Funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[3]	0		0
Japan | Defined Benefit Plan, Equity Securities | Other than Japan Pooled Funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[3]	0		0
Japan | Defined Benefit Plan, Debt Security | Japan Pooled Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		26,133	[4]	19,243	[5]
Japan | Defined Benefit Plan, Debt Security | Japan Pooled Funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0	[4]	0	[5]
Japan | Defined Benefit Plan, Debt Security | Japan Pooled Funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0	[4]	0	[5]
Japan | Defined Benefit Plan, Debt Security | Japan Pooled Funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0	[4]	0	[5]
Japan | Defined Benefit Plan, Debt Security | Other than Japan Pooled Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[6]	33,930		27,382
Japan | Defined Benefit Plan, Debt Security | Other than Japan Pooled Funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[6]	0		0
Japan | Defined Benefit Plan, Debt Security | Other than Japan Pooled Funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[6]	0		0
Japan | Defined Benefit Plan, Debt Security | Other than Japan Pooled Funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[6]	0		0
Japan | Other Plan Asset | Life Insurance Company General Accounts
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[7]	28,591		27,482
Japan | Other Plan Asset | Life Insurance Company General Accounts | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[7]	0		0
Japan | Other Plan Asset | Life Insurance Company General Accounts | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[7]	28,591		27,482
Japan | Other Plan Asset | Life Insurance Company General Accounts | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[7]	0		0
Japan | Other Plan Asset | Other Investment
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[8]	4,485		5,162
Japan | Other Plan Asset | Other Investment | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[8]	0		0
Japan | Other Plan Asset | Other Investment | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[8]	4,485		5,162
Japan | Other Plan Asset | Other Investment | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[8]	0		0
Overseas plans
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		96,994		96,837		¥ 93,338
Overseas plans | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		87,470		89,393
Overseas plans | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		9,213		7,052
Overseas plans | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Overseas plans | Defined Benefit Plan, Equity Securities | Other than Japan Pooled Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[3]	311		392
Overseas plans | Defined Benefit Plan, Equity Securities | Other than Japan Pooled Funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[3]	0		0
Overseas plans | Defined Benefit Plan, Equity Securities | Other than Japan Pooled Funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[3]	0		0
Overseas plans | Defined Benefit Plan, Equity Securities | Other than Japan Pooled Funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[3]	0		0
Overseas plans | Defined Benefit Plan, Equity Securities | Other than Japan Shares
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		36,848		42,124
Overseas plans | Defined Benefit Plan, Equity Securities | Other than Japan Shares | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		36,848		42,124
Overseas plans | Defined Benefit Plan, Equity Securities | Other than Japan Shares | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Overseas plans | Defined Benefit Plan, Equity Securities | Other than Japan Shares | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Overseas plans | Defined Benefit Plan, Debt Security | Other than Japan Government Bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		50,622		47,269
Overseas plans | Defined Benefit Plan, Debt Security | Other than Japan Government Bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		50,622		47,269
Overseas plans | Defined Benefit Plan, Debt Security | Other than Japan Government Bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Overseas plans | Defined Benefit Plan, Debt Security | Other than Japan Government Bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Overseas plans | Defined Benefit Plan, Debt Security | Other than Japan Municipal Bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		4,849		4,640
Overseas plans | Defined Benefit Plan, Debt Security | Other than Japan Municipal Bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Overseas plans | Defined Benefit Plan, Debt Security | Other than Japan Municipal Bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		4,849		4,640
Overseas plans | Defined Benefit Plan, Debt Security | Other than Japan Municipal Bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Overseas plans | Other Plan Asset | Life Insurance Company General Accounts
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[7]	355		588
Overseas plans | Other Plan Asset | Life Insurance Company General Accounts | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[7]	0		0
Overseas plans | Other Plan Asset | Life Insurance Company General Accounts | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[7]	355		588
Overseas plans | Other Plan Asset | Life Insurance Company General Accounts | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[7]	0		0
Overseas plans | Other Plan Asset | Other Investment
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[8]	4,009		1,824
Overseas plans | Other Plan Asset | Other Investment | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[8]	0		0
Overseas plans | Other Plan Asset | Other Investment | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[8]	4,009		1,824
Overseas plans | Other Plan Asset | Other Investment | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[8]	¥ 0		¥ 0

[1] These funds invest in listed shares including shares of ORIX Corporation in the amounts of ¥17 million at March 31, 2020.

[2] These funds invest in listed shares including shares of ORIX Corporation in the amounts of ¥42 million at March 31, 2019.

[3] These funds invest in listed shares.

[4] These funds invest approximately 70% in Japanese government bonds, approximately 10% in Japanese municipal bonds, and approximately 20% in Japanese corporate bonds. These funds include corporate bonds of ORIX Corporation in the amounts of ¥1,192 million at March 31, 2020.

[5] These funds invest approximately 60% in Japanese government bonds, approximately 10% in Japanese municipal bonds, and approximately 30% in Japanese corporate bonds. These funds include corporate bonds of ORIX Corporation in the amounts of ¥1,578 million at March 31, 2019.

[6] These funds invest entirely in foreign government bonds.

[7] Life insurance company general accounts are accounts with guaranteed capital and minimum interest rate, in which life insurance companies manage funds on several contracts.

[8] Others include derivative instruments held for hedging change in the fair value of equity securities, and short-term instruments.