Commitments and Contingencies - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2015 CAD
Commitment And Contingencies [Line Items]
Accrued liability for legal contingencies	$ 20,000,000
Undiscounted reserve for environmental remediation	62,000,000
Administrative penalty | CAD		CAD 16,500
Working Capital Adjustments [Member] | Wheatstone Lng and Kitimat Lng [Member]
Commitment And Contingencies [Line Items]
Purchase price adjustments amount	175,000,000
All Other Adjustments [Member] | Wheatstone Lng and Kitimat Lng [Member]
Commitment And Contingencies [Line Items]
Purchase price adjustments amount	$ 214,000,000
Escheat Audits [Member]
Commitment And Contingencies [Line Items]
Loss contingency, period of occurrence	2004 through 2009	2004 through 2009
Maximum possible loss from contingency	$ 237,000
Minimum [Member] | Apollo Exploration Lawsuit [Member]
Commitment And Contingencies [Line Items]
Plaintiffs alleged damages	1,100,000,000
Minimum [Member] | Louisiana Restoration [Member]
Commitment And Contingencies [Line Items]
Plaintiffs alleged damages	7,000,000
Maximum [Member] | Louisiana Restoration [Member]
Commitment And Contingencies [Line Items]
Plaintiffs alleged damages	$ 96,000,000