Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Income Tax Disclosure [Line Items]
Restructuring and other charges	$ 0	$ 0		$ 439	$ 0
Deferred tax assets, valuation allowances relating to net operating losses in certain countries	$ 156			$ 156		$ 190
US federal statutory rate	35.00%		35.00%	35.00%	35.00%
Domestic Country
Income Tax Disclosure [Line Items]
Restructuring and other charges				$ 93
Foreign Country
Income Tax Disclosure [Line Items]
Restructuring and other charges				$ 346