Profit Sharing, Retirement Savings Plans and Defined Benefit Pension Plans - Fair Values of Pension Plan Assets, by Asset Category and Level of Fair Values (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 1,045.0	$ 1,023.2	$ 961.6
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4.8	6.7
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	917.0	929.0
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	123.2	87.5
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9.6	10.8
Cash and Cash Equivalents [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4.8	6.7
Cash and Cash Equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4.8	4.1
Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	495.2	497.4
Fixed Income Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	495.2	497.4
Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	392.8	418.2
Equity Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	392.8	418.2
Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	147.4	96.8
Other [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	24.2	9.3
Other [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 123.2	$ 87.5