Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Line Items]
Unrecognized tax benefits that would affect the effective tax rate on income if recognized	$ (129)
Increase in valuation allowance expected to offset a portion of the potential tax benefit	99
Unrecognized tax benefits related to tax positions for which ultimate deductibility is highly certain, but timing is uncertain	(18)
The lower range of unrecognized tax benefits expected to reverse within the next 12 months due to expiration of statutes of limitation and audit settlements	(4)
The higher range of unrecognized tax benefits expected to reverse within the next 12 months due to expiration of statutes of limitation and audit settlements	(10)
Accrued interest related to uncertain tax positions	8	28
Interest and penalties recognized in income tax expense (benefit)	(20)	9
U.S. Internal Revenue Service [Member] | Minimum [Member]
Income Tax Disclosure [Line Items]
Tax year currently under routine examination	2007
U.S. Internal Revenue Service [Member] | Maximum [Member]
Income Tax Disclosure [Line Items]
Tax year currently under routine examination	2013
Additions [Member]
Income Tax Disclosure [Line Items]
(Increase) decrease in valuation allowances	(38)	(426)	(138)
Reductions [Member]
Income Tax Disclosure [Line Items]
(Increase) decrease in valuation allowances	142	59	37
Changes in Judgment Regarding Future Realizability of Deferred Tax Assets [Member] | Additions [Member]
Income Tax Disclosure [Line Items]
(Increase) decrease in valuation allowances	(2)	(23)
Changes in Judgment Regarding Future Realizability of Deferred Tax Assets [Member] | Reductions [Member]
Income Tax Disclosure [Line Items]
(Increase) decrease in valuation allowances			$ 17