Subsequent Event - Summary of Discontinued Operation on Assets and Liabilities of Business (Parenthetical) (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill gross	$ 3,147.1	$ 3,279.3
Accumulated goodwill impairment losses	2,592.9	2,690.8
Business Services
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill gross	2,627.6	2,759.8
Accumulated goodwill impairment losses	2,338.8	$ 2,436.7
Disposition by Sale | Business Services | Print Logistics
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill gross	100.9
Accumulated goodwill impairment losses	$ 68.5