Income Tax - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2012	Jun. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Income Tax Examination [Line Items]
Charges (credits) pretax		$ (664)	$ 32	$ 68	$ (572)
Deferred tax assets, valuation allowances relating to net operating losses in certain countries	237				237		256
US statutory federal rate	35.00%		35.00%		35.00%	35.00%
Domestic Country
Income Tax Examination [Line Items]
Charges (credits) pretax			20	41	53
Foreign Country
Income Tax Examination [Line Items]
Charges (credits) pretax			$ 12	$ 27	$ (625)