Capital Stock - Net Income (loss) Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Basic:
Loss from continuing operations	$ (244)	$ (980)	$ (616)	$ (2,076)
Loss from discontinued operations	0	120	0	(118)
NET LOSS ATTRIBUTABLE TO COMMON STOCK	$ (244)	$ (860)	$ (616)	$ (2,194)
Loss from continuing operations, shares	379	378	379	377
Loss from discontinued operations, shares	379	378	379	377
Loss attributable to common stock, shares	379	378	379	377
Basic loss from continuing operations, per share	$ (0.65)	$ (2.60)	$ (1.63)	$ (5.50)
Basic loss from discontinued operations, per share	0.00	0.32	0.00	(0.31)
Basic net loss per share	$ (0.65)	$ (2.28)	$ (1.63)	$ (5.81)
Diluted:
Loss from continuing operations	$ (244)	$ (980)	$ (616)	$ (2,076)
Loss from discontinued operations	0	120	0	(118)
Loss attributable to common stock	$ (244)	$ (860)	$ (616)	$ (2,194)
Loss from continuing operations, shares	379	378	379	377
Loss from discontinued operations, shares	379	378	379	377
Loss attributable to common stock, shares	379	378	379	377
Diluted loss from continuing operations, per share	$ (0.65)	$ (2.60)	$ (1.63)	$ (5.50)
Diluted loss from discontinued operations, per share	0.00	0.32	0.00	(0.31)
Diluted net loss per share	$ (0.65)	$ (2.28)	$ (1.63)	$ (5.81)