Retirement Benefits - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012 Investment	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligations in excess of plan assets, projected benefit obligation	$ 204,300,000	$ 520,700,000
Accumulated benefit obligations in excess of plan assets, fair value of plan assets	139,600,000	429,900,000
Accumulated benefit obligation, pension benefit plans	638,000,000	578,200,000
Accumulated benefit obligations in excess of plan assets, accumulated benefit obligation	193,600,000	495,500,000
Multi employer pension plan contributions	6,398,000	6,027,000	6,125,000
Defined contribution plans contributions charged to expense	7,600,000	8,000,000	8,300,000
Target Allocation	100.00%
Concentration of risk description	As of December 31, 2012, approximately 99 percent of plan assets were under management by a single investment management company in six individual commingled equity and debt index funds. Of these six funds, three funds held assets individually in excess of ten percent of our total plan assets.
Plan assets held under management by single investment company	99.00%
Number of commingled debt and equity index funds	6
Number of asset funds	3
Voluntary contributions to Domestic Pension Benefit Plans	76,000,000
United States
Defined Benefit Plan Disclosure [Line Items]
Equity securities, target allocation as percentage of total equity securities	85.00%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Multi Employer Funded Status	65.00%
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	58.00%
Equity Securities | United States
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	49.00%
Debt securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	42.00%
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation discount rate	3.60%	4.90%
Benefit obligation rate of compensation increase	3.50%	3.50%
Net periodic benefit cost discount rate	4.90%	5.50%	5.90%
Net periodic benefit cost rate of compensation increase	3.50%	3.50%	3.50%
Projected Benefit Obligation In Excess Of Plan Assets
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligations in excess of plan assets, projected benefit obligation	204,300,000	609,700,000
Accumulated benefit obligations in excess of plan assets, fair value of plan assets	139,600,000	509,900,000
Unfunded International Defined Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligations in excess of plan assets, projected benefit obligation	$ 57,200,000	$ 42,000,000