Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments	$ 604,000,000	$ 1,920,000,000	$ 1,919,000,000	$ 0
Asset impairments		1,700,000,000
Impairment of equity method investment		148,000,000
Inventory write-downs		55,000,000
Goodwill impairment charges			1,300,000,000
Impairment of assets held for sale and other assets			604,000,000
Cash and cash equivalents	769,000,000	1,467,000,000	769,000,000	1,906,000,000	$ 160,000,000
Allowance for doubtful accounts	98,000,000	103,000,000	98,000,000	78,000,000
Increase in allowance for doubtful accounts		5,000,000
Additional provisions on allowance for doubtful accounts		40,000,000
Allowance for doubtdul accounts written off		35,000,000
Capitalized internal costs	43,865,000,000	$ 12,828,000,000	43,865,000,000
Discount rate		10.00%
Write-down of the carrying value of Oil and Gas properties, net of tax		$ 16,620,000,000	3,068,000,000	541,000,000
Significant portion of reserve quantity		Greater than 25 percent
Gain (loss) recorded on divestitures		$ (1,300,000,000)		0
Gathering, transmission and processing facilities	5,440,000,000	1,052,000,000	5,440,000,000
Accumulated depreciation	55,382,000,000	79,706,000,000	55,382,000,000
Fair value of GTP assets		306,000,000
Goodwill				1,400,000,000
Accounts payable		129,000,000	229,000,000
Net cost of third party gas		$ 37,000,000	46,000,000	34,000,000
Maximum percentage of production available to contract partners		40.00%
Other foreign currency gains and (losses)		$ (11,000,000)	8,000,000	(30,000,000)
Benefit of tax deductions in excess of recognized compensation cost		1,000,000	35,000	1,000,000
GTP Facilities [Member]
Schedule Of Significant Accounting Policies [Line Items]
Gathering, transmission and processing facilities	5,400,000,000	1,100,000,000	5,400,000,000
Accumulated depreciation	1,700,000,000	160,000,000	1,700,000,000
Gain (loss) on the sale of GTP facilities		59,000,000	(180,000,000)	0
Other Property and Equipment [Member]
Schedule Of Significant Accounting Policies [Line Items]
Accumulated depreciation	673,000,000	693,000,000	673,000,000
Argentina [Member]
Schedule Of Significant Accounting Policies [Line Items]
Write-down of the carrying value of Oil and Gas properties, net of tax				118,000,000
Gain (loss) recorded on divestitures			(539,000,000)
United States [Member]
Schedule Of Significant Accounting Policies [Line Items]
Capitalized internal costs	23,947,000,000	5,356,000,000	23,947,000,000
Write-down of the carrying value of Oil and Gas properties, net of tax		12,602,000,000	2,844,000,000	356,000,000
Goodwill				1,000,000,000
Non-cash impairments of goodwill	1,000,000,000
Mobil North Sea Limited [Member]
Schedule Of Significant Accounting Policies [Line Items]
Goodwill				163,000,000
Non-cash impairments of goodwill	163,000,000
Canada, Dollars
Schedule Of Significant Accounting Policies [Line Items]
Goodwill				103,000,000
Non-cash impairments of goodwill	103,000,000
Egypt [Member]
Schedule Of Significant Accounting Policies [Line Items]
Goodwill impairment charges				0
Capitalized internal costs	4,055,000,000	3,547,000,000	4,055,000,000
Write-down of the carrying value of Oil and Gas properties, net of tax		281,000,000
Goodwill	87,000,000	87,000,000	87,000,000	87,000,000
Australia [Member]
Schedule Of Significant Accounting Policies [Line Items]
Capitalized internal costs	5,640,000,000		5,640,000,000
Australia [Member] | Discontinued Operations [Member]
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments			439,000,000
Wheatstone LNG [Member]
Schedule Of Significant Accounting Policies [Line Items]
Gain (loss) recorded on divestitures		(922,000,000)
Apache Corporation [Member]
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments		112,000,000	175,000,000
Cash and cash equivalents	267,000,000	378,000,000	267,000,000	155,000,000
Capitalized internal costs	$ 373,000,000	$ 297,000,000	$ 373,000,000	$ 401,000,000
Minimum [Member]
Schedule Of Significant Accounting Policies [Line Items]
Voting interest required for consolidation of investments		50.00%
Minimum [Member] | Other Property and Equipment [Member]
Schedule Of Significant Accounting Policies [Line Items]
Useful lives of gas gathering, transmission and processing facilities		3 years
Maximum [Member]
Schedule Of Significant Accounting Policies [Line Items]
Voting interest required for consolidation of investments		50.00%
Maximum [Member] | Other Property and Equipment [Member]
Schedule Of Significant Accounting Policies [Line Items]
Useful lives of gas gathering, transmission and processing facilities		20 years