Income Taxes - Components of Income Tax Provision (Benefit) for Continuing Operations (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
United States - Federal, Current income tax expense (benefit)	$ (7)	$ (1)	$ 8
United States - Federal, Deferred income tax expense (benefit)	(995)	156	103
United States - State, Current & Deferred tax expense (benefit)	(61)	57	9
United States, Current & Deferred income tax expense (benefit)	(1,063)	212	120
Foreign, Current income tax expense (benefit)	4	453	941
Foreign, Deferred income tax expense (benefit)	(231)	79	186
Foreign, Current & Deferred income tax expense (benefit)	(227)	532	1,127
Provision (benefit) for income taxes - before adjustments due to income tax law changes	(1,290)	744	1,247
Adjustment of deferred taxes for foreign income tax law changes	(9)	0	(682)
Total provision (benefit) for income taxes	$ (1,299)	$ 744	$ 565