Benefit Plans - Plan Assets Using Fair Value Methodologies (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 572.3	$ 575.2
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7.7	27.4
Fixed income | Foreign Government
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	262.2	164.3
Fixed income | US Treasury Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	75.5	69.4
Fixed income | Collateralized Mortgage Backed Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8.7	23.4
Fixed income | Other securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	34.1	28.1
Equity securities | U S Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7.3	6.7
Equity securities | U S Large Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	43.5	89.0
Equity securities | International Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	101.9	89.8
Equity securities | US Long/Short Equity Fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.6	47.6
Other Investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	30.8	29.5
Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.8	6.2
Fair Value, Inputs, Level 1 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.8	6.2
Fair Value, Inputs, Level 1 | Equity securities | U S Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Fair Value, Inputs, Level 1 | Equity securities | International Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	551.5	550.7
Fair Value, Inputs, Level 2 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5.9	21.2
Fair Value, Inputs, Level 2 | Fixed income | Foreign Government
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	262.2	164.3
Fair Value, Inputs, Level 2 | Fixed income | US Treasury Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	75.5	69.4
Fair Value, Inputs, Level 2 | Fixed income | Collateralized Mortgage Backed Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8.7	23.4
Fair Value, Inputs, Level 2 | Fixed income | Other securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	34.1	28.1
Fair Value, Inputs, Level 2 | Equity securities | U S Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7.3	6.7
Fair Value, Inputs, Level 2 | Equity securities | U S Large Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	43.5	89.0
Fair Value, Inputs, Level 2 | Equity securities | International Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	101.9	89.8
Fair Value, Inputs, Level 2 | Equity securities | US Long/Short Equity Fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.6	47.6
Fair Value, Inputs, Level 2 | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	11.8	11.2
Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19.0	18.3
Fair Value, Inputs, Level 3 | Fixed income | Foreign Government
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Fair Value, Inputs, Level 3 | Fixed income | Collateralized Mortgage Backed Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Fair Value, Inputs, Level 3 | Fixed income | Other securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Fair Value, Inputs, Level 3 | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 19.0	$ 18.3