Contingencies - Additional Information (Detail) - Contingencies Disclosed in Contingencies Note $ in Millions	Dec. 31, 2015 USD ($)
Loss Contingencies [Line Items]
Accrual for disclosed loss contingencies, current, ending balance	$ 550
Accrual for disclosed loss contingencies, noncurrent, ending balance	10
Amount not accrued for estimated maximum losses for disclosed loss contingencies	$ 1,500