Identifiable Assets for Business Segments and Discontinued Operations (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Discontinued operations	$ 114.9	$ 130.5
Identifiable assets	13,378.7	13,484.9
U.S. Companies
Segment Reporting Information [Line Items]
Identifiable assets	8,962.6	8,909.6
Chaucer
Segment Reporting Information [Line Items]
Identifiable assets	$ 4,301.2	$ 4,444.8