Income Taxes - Net Deferred Tax Liability (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Deferred income	$ 105	$ 20
U.S. and state net operating losses	1,095	329
Foreign net operating losses	1,424	1,507
Tax credits and other tax incentives	62	82
Foreign tax credits	2,226	2,090
Accrued expenses and liabilities	153	136
Asset retirement obligation	875	1,037
Property and equipment	1,189	1,534
Total deferred tax assets	7,129	6,735
Valuation allowance	(5,401)	(5,434)	$ (1,564)	$ (598)
Net deferred tax assets	1,728	1,301
Deferred tax liabilities:
Deferred income	0	140
Investment in foreign subsidiaries	1,872	1,903
Equity investments	23	5
Property and equipment	1,533	1,773
Other	5	4
Total deferred tax liabilities	3,433	3,825
Net deferred income tax liability	$ 1,705	$ 2,524