Allocation of Plan Assets, Pension Plan (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Private Equity Funds | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	$ 43.4	$ 38.9	$ 30.1
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	3,707.3	3,215.3	2,849.6
Pension Plans, Defined Benefit | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	2,149.3	2,155.8
Pension Plans, Defined Benefit | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	1,514.6	1,020.6
Pension Plans, Defined Benefit | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	43.4	38.9
Pension Plans, Defined Benefit | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	79.6	56.9
Pension Plans, Defined Benefit | Cash and Cash Equivalents | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	51.6	27.4
Pension Plans, Defined Benefit | Cash and Cash Equivalents | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	28.0	29.5
Pension Plans, Defined Benefit | Cash and Cash Equivalents | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets
Pension Plans, Defined Benefit | Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	2,658.7	2,169.0
Pension Plans, Defined Benefit | Equity Funds | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	1,839.3	1,887.4
Pension Plans, Defined Benefit | Equity Funds | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	819.4	281.6
Pension Plans, Defined Benefit | Equity Funds | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets
Pension Plans, Defined Benefit | Fixed Income Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	795.3	828.0
Pension Plans, Defined Benefit | Fixed Income Funds | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	255.0	240.5
Pension Plans, Defined Benefit | Fixed Income Funds | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	540.3	587.5
Pension Plans, Defined Benefit | Fixed Income Funds | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets
Pension Plans, Defined Benefit | Derivative
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	3.9	8.9
Pension Plans, Defined Benefit | Derivative | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	3.4	0.5
Pension Plans, Defined Benefit | Derivative | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	0.5	8.4
Pension Plans, Defined Benefit | Derivative | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets
Pension Plans, Defined Benefit | Real Estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	126.4	113.6
Pension Plans, Defined Benefit | Real Estate | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets
Pension Plans, Defined Benefit | Real Estate | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	126.4	113.6
Pension Plans, Defined Benefit | Real Estate | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets
Pension Plans, Defined Benefit | Private Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	43.4	38.9
Pension Plans, Defined Benefit | Private Equity Funds | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets
Pension Plans, Defined Benefit | Private Equity Funds | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets
Pension Plans, Defined Benefit | Private Equity Funds | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of the company's benefit plan assets	$ 43.4	$ 38.9