Pension and Other Postretirement Benefits - Additional Information (Detail) - USD ($)		3 Months Ended	12 Months Ended
	Aug. 01, 2016	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Average duration refined yield curve model parallels the plans, years				11 years
Average period of historical returns used to calculate expected future returns, in years				5 years
Expected long term rate of return on plan assets				7.75%	7.75%	8.00%
Decrease in expected long-term rate of return				0.25%
Health care cost trend rate assumed for next year				5.50%	5.50%	5.50%
Health care cost trend rate				4.50%	4.50%	4.50%
Number of years over actual annual health care cost trend experience					3 years
Cash contribution to pension plans				$ 290,000,000	$ 470,000,000	$ 501,000,000
Minimum required cash contribution to pension plan		$ 50,000,000			310,000,000
Cash contribution term to pension plan		30 months
Aggregate cash cash contribution to pension plan		$ 150,000,000
Expenses related to saving and investment plans				$ 71,000,000	$ 83,000,000	83,000,000
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate					9.60%
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate					3.60%
Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long term rate of return on plan assets			7.75%
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage increase in rate of compensation				3.50%
Average period over which rate of compensation increases, years				5 years
Change in interest cost component of net periodic benefit cost determination						84,000,000
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Change in interest cost component of net periodic benefit cost determination						$ 14,000,000
United Steelworkers Labor Agreement [Member]
Defined Benefit Plan Disclosure [Line Items]
Increase in pension liability, plan amendment	$ 845,000,000
Accumulated (increase) decrease in net actuarial loss after-tax, plan amendment	$ (551,000,000)
Foreign Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Average period of historical returns used to calculate expected future returns, in years				4 years
United States Pension Plan of US Entity [Member]
Defined Benefit Plan Disclosure [Line Items]
Minimum required cash contribution to pension plan					$ 290,000,000