Pension and Postretirement Benefit Plans - Company's Share of Amounts Included in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Prior service benefit	$ (59.5)	$ (64.9)
Net actuarial loss	125.1	141.9
Total	$ 65.6	$ 77.0

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.

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Balance Type:	debit
Period Type:	duration