Reconciliation Of Changes In Benefit Obligations And Fair Value Of Plan Assets (Parenthetical) (Detail) (Pension Plans, U S Plans, USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Pension Plans \| U S Plans
Defined Benefit Plan Disclosure [Line Items]
Employer contributions, discretionary contribution	$ 10.0

Amount of discretionary contributions made by an employer to a defined contribution plan.

No definition available.

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