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Pension and Post-retirement Benefits - Additional Information (Detail) - USD ($) $ in Millions		12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Defined contribution expense		$ 22	$ 5	$ 5
Health care cost trend rates in 2019	6.50%	6.50%
Health care cost trend rates projected to decline in 2025	5.00%	5.00%
Year health care cost trend rates projected to decline		2025
Contributions to multi-employer plans		$ 11
Fixed Income [Member] \| Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target weighted-average asset allocations by asset category	20.00%	20.00%
Fixed Income [Member] \| Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target weighted-average asset allocations by asset category	25.00%	25.00%
Equity Securities [Member] \| Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target weighted-average asset allocations by asset category	70.00%	70.00%
Equity Securities [Member] \| Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target weighted-average asset allocations by asset category	75.00%	75.00%
Other Investments [Member] \| Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target weighted-average asset allocations by asset category	5.00%	5.00%
Other Investments [Member] \| Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target weighted-average asset allocations by asset category	10.00%	10.00%
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation for all defined benefit pension plans	$ 1,400	$ 1,400	$ 511
CB&I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution expense	$ 16