Income Taxes - Total Provision for Income Taxes (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current taxes:
Federal	$ 363	$ (10)	$ (29)
State	41	1
Foreign	(95)	1,186	1,648
Current tax, net	309	1,177	1,619
Deferred taxes:
Federal	(4,157)	(130)	509
State	(90)	(43)	44
Foreign	(1,531)	(341)	(244)
Deferred taxes, net	(5,778)	(514)	309
Total	$ (5,469)	$ 663	$ 1,928