Income Taxes - Taxes Receivable (Payable) Table (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Components of Income Tax Receivable (Payable) [Line Items]
Income taxes receivable	$ 1,107	$ 128
Total net income taxes receivable (payable)	1,098	(24)
Accounts Receivable - Other [Member]
Components of Income Tax Receivable (Payable) [Line Items]
Income taxes receivable	1,046	93
Other Assets [Member]
Components of Income Tax Receivable (Payable) [Line Items]
Income taxes receivable	61	35
Accrued Expense [Member]
Components of Income Tax Receivable (Payable) [Line Items]
Income taxes (payable)	$ (9)	$ (152)