Assets Reconciliation (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 15,546	$ 20,962	$ 26,138
Cash and equivalents	2,801	2,213	2,925	$ 2,733
Deferred income taxes	629	354
PP&E, net	4,289	4,386	4,434
Assets held for disposition	50	245
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	10,722	11,241	11,843
Material Reconciling Items
Segment Reporting, Asset Reconciling Item [Line Items]
Cash and equivalents	2,801	2,213	2,925
Deferred income taxes	629	354	531
PP&E, net	805	932	1,039
Assets held for disposition	50	245	9,363
Corporate, Non-Segment
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 539	$ 5,977	$ 437