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Pension Plans - Reconciliation of Fair Value of Plan Assets Measured Using Significant Unobservable Inputs (Detail) - United Kingdom Plan [Member] - Non-financial Assets and Liabilities (Level 3 Measurement) [Member] - Other Assets [Member] - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2016 | Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |
Beginning balance | $ 171.9 | $ 0.0
Realized/unrealized gains/(losses): |  |
Relating to assets still held at the reporting date | 16.8 | 0.0
Relating to assets sold during the period | 0.0 | 0.0
Purchases, issuances and settlements | (6.7) | 171.9
Exchange effect | (29.1) | 0.0
Ending balance | $ 152.9 | $ 171.9

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- Definition Fair value measurement with unobservable inputs reconciliation recurring basis asset gains and losses. + References No definition available. + Details
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- Definition Amount of purchases, (sales), issuances and (settlements) of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
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