Employee Retirement Plans - Schedule of Estimated Amount that will be Amortized from Accumulated Other Comprehensive Loss into Net Periodic Benefit Cost in Next Fiscal Year (Detail) $ in Millions	12 Months Ended
Dec. 31, 2015 USD ($)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss	$ (2.8)
Total	(2.8)
OPEB Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service credit	12.2
Actuarial loss	(0.1)
Total	$ 12.1

Amount included in accumulated other comprehensive income (AOCI) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position, including gain (loss), prior service cost (credit), and transition asset (obligation).

No definition available.

Name:	us-gaap_DefinedBenefitPlanAmountToBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossNextFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration