Investments - Additional Information (Detail) - Elysis TM Limited Partnership [Member] $ in Millions	Jan. 31, 2020 USD ($)
Schedule of Equity Method Investments [Line Items]
Basis in investment, due to share of losses	$ 0
Unrecognized losses	$ 21

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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