Employee Benefit Plans - Additional Information (Detail) $ in Millions	Jun. 30, 2015 USD ($)
Defined Benefit Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Expected contribution during 2015	$ 19.6
OPEB
Defined Benefit Plan Disclosure [Line Items]
Expected contribution during 2015	$ 1.3

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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