Capital Stock - Net Income (loss) Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015		Sep. 30, 2016	Sep. 30, 2015
Basic:
Loss from continuing operations	$ (574)	$ (4,126)		$ (1,190)	$ (6,202)
Loss from discontinued operations	(33)	(17)		(33)	(135)
NET LOSS ATTRIBUTABLE TO COMMON STOCK	$ (607)	$ (4,143)	[1]	$ (1,223)	$ (6,337)	[1]
Loss from continuing operations, shares	380	378		379	378
Loss from discontinued operations, shares	380	378		379	378
Loss attributable to common stock, shares	380	378	[1]	379	378	[1]
Basic loss from continuing operations, per share	$ (1.51)	$ (10.91)	[1]	$ (3.14)	$ (16.42)	[1]
Basic loss from discontinued operations, per share	(0.09)	(0.04)	[1]	(0.08)	(0.36)	[1]
Basic net loss per share	$ (1.60)	$ (10.95)	[1]	$ (3.22)	$ (16.78)	[1]
Diluted:
Loss from continuing operations	$ (574)	$ (4,126)		$ (1,190)	$ (6,202)
Loss from discontinued operations	(33)	(17)		(33)	(135)
Loss attributable to common stock	$ (607)	$ (4,143)		$ (1,223)	$ (6,337)
Loss from continuing operations, shares	380	378		379	378
Loss from discontinued operations, shares	380	378		379	378
Loss attributable to common stock, shares	380	378	[1]	379	378	[1]
Diluted loss from continuing operations, per share	$ (1.51)	$ (10.91)	[1]	$ (3.14)	$ (16.42)	[1]
Diluted loss from discontinued operations, per share	(0.09)	(0.04)	[1]	(0.08)	(0.36)	[1]
Diluted net loss per share	$ (1.60)	$ (10.95)	[1]	$ (3.22)	$ (16.78)	[1]

[1] Financial information for 2015 has been recast to reflect retrospective application of the successful efforts method of accounting. See Note 1.