Acquisitions and Divestitures - Summary of Carrying Amount of Major Assets and Liabilities Associated with Disposition - Australia Divestitures (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
ASSETS
Current assets	$ 3,752	$ 6,415
Oil and gas assets, net	12,828	43,865
Total assets	18,842	55,952	$ 51,966
LIABILITIES
Current liabilities	1,841	3,664
Asset retirement obligations	2,562	3,048
Non-current deferred tax liability	1,072	9,499
Other long-term liabilities	$ 362	359
Australia [Member]
ASSETS
Oil and gas assets, net		5,640
Divestiture [Member] | Australia [Member]
ASSETS
Current assets		1,992
Oil and gas assets, net		5,639
GTP and other assets, net		877
Total assets		8,508
LIABILITIES
Current liabilities		606
Asset retirement obligations		517
Non-current deferred tax liability		922
Other long-term liabilities		33
Total liabilities		$ 2,078