Cash Flow Information - Summary of Cash, Cash Equivalents and Restricted Cash (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents	¥ 982,666	¥ 1,161,032
Restricted Cash	152,618	122,548
Cash, Cash Equivalents and Restricted Cash	¥ 1,135,284	¥ 1,283,580	¥ 1,405,117	¥ 1,133,212

Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage. Excludes amount for disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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