Postretirement Benefit Plans - Net Loss and Prior Service Cost that will be Amortized from Accumulated Other Comprehensive Income Loss (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 14.6
Prior service cost (credit)	0.4
Total	15.0
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	9.5
Prior service cost (credit)	0.8
Total	10.3
Others Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	5.1
Prior service cost (credit)	(0.4)
Total	$ 4.7

The amounts in accumulated other comprehensive income related to gains and losses that are not recognized immediately and are expected to be recognized as components of net periodic benefit cost over the next fiscal year that follows the most recent annual statement of financial position presented.

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The amounts in accumulated other comprehensive income related to prior service cost or credit expected to be recognized as components of net periodic benefit cost over the next fiscal year that follows the most recent annual statement of financial position presented.

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- Definition

The aggregate amount in accumulated other comprehensive income expected to be recognized as a component of net periodic benefit cost over the fiscal year that follows the most recent annual statement of financial position presented, including the net gain (loss), net prior service cost or credit, and net transition asset or obligation.

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