Long Term Debt (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Other debt	$ 116	$ 111
Total long-term debt	16,296	7,041
Less: unamortized discounts and deferred financing costs	(1,035)	(899)
Total long-term debt, net	15,261	6,142
1.85% to 3.80%, due 2016 to 2045
Debt Instrument [Line Items]
Notes	8,150	1,400
4.07% to 5.72%, due 2019 to 2046
Debt Instrument [Line Items]
Notes	6,089	3,589
6.15% to 9.13%, due 2016 to 2036
Debt Instrument [Line Items]
Notes	$ 1,941	$ 1,941