Comprehensive Income - Additional Information (Detail) $ in Millions	9 Months Ended
Jun. 30, 2019 USD ($)
Maximum
Accumulated Other Comprehensive Income (Loss) [Line Items]
Changes in accumulated other comprehensive loss, net of related taxes	$ 1

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.

No definition available.

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