Other Current Liabilities - Details of Other Current Liabilities (Detail) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Payables and Accruals [Abstract]
Accrued operating expenses	$ 139	$ 163
Accrued exploration and development	668	1,606
Accrued compensation and benefits	158	204
Accrued interest	107	160
Accrued income taxes	296	54
Current asset retirement obligation	28	37
Other	112	230
Total Other current liabilities	$ 1,508	$ 2,454