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	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 668.7	$ 776.2	$ 771.8
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3.5	5.6
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	246.0	360.8
Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	165.4	86.5
NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	253.8	323.3
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	36.5	7.5
Cash and cash equivalents | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3.5	5.6
Cash and cash equivalents | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4.5	1.9
Cash and cash equivalents | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Cash and cash equivalents | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	28.5	0.0
Fixed income funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	283.4	385.9
Fixed income funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Fixed income funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	131.7	162.5
Fixed income funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Fixed income funds | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	151.7	223.4
Equity funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	147.1	257.6
Equity funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Equity funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	89.7	177.9
Equity funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Equity funds | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	57.4	79.7
Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	201.7	125.2
Other | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	20.1	18.5
Other | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	165.4	86.5
Other | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 16.2	$ 20.2