Exit and Disposal Costs - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014 Employee Severance [Member]	Dec. 31, 2013 Employee Severance [Member]	Sep. 30, 2014 Facility and Other Exit Costs [Member]
Restructuring Cost And Reserve [Line Items]
Enhanced severance benefit arrangements	$ 1
Accrued restructuring costs	$ 164	$ 136	$ 171	$ 28
Percentage of accrued employee severance to be paid in current year	60.00%
Percentage of accrued employee severance to be paid in next year	35.00%
Percentage of accrued facility and other exit costs to be paid in current year	30.00%