Guarantees and Contingencies - Additional Information (Detail) - USD ($)			1 Months Ended
	Jan. 18, 2017	Mar. 04, 2016	Apr. 30, 2014	Mar. 31, 2014
Loss Contingencies [Line Items]
Estimated remediation cost related to Lower Passaic River in New Jersey		$ 1,380,000,000	$ 1,700,000,000
N Y
Loss Contingencies [Line Items]
Estimated remediation cost related to Lower Passaic River in New Jersey				$ 506,000,000
Legacy conventional North Dakota Assets
Loss Contingencies [Line Items]
Penalty assessed under consent decree	$ 922,000
Initial penalty payment under consent decree	$ 55,000