Other Long-Term Liabilities Long Term Finance Lease Obligation (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Other Liabilities Disclosure [Abstract]
Gross finance lease obligations	$ 3,233
Less imputed interest	(650)
Present value of net minimum lease payments	2,583
Less current portion of finance lease obligations	(144)	$ (99)
Total long-term finance lease obligations	$ 2,439	$ 1,736