Asset Impairments and Unusual Items - Components of (Income) Expense from Divestitures, Asset Impairments (Other Than Goodwill) and Unusual Items (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Extraordinary And Unusual Items [Abstract]
(Income) expense from divestitures				$ (8)		$ 1
Asset impairments (other than goodwill)	30	45	34	472	79	8
(Income) expense from divestitures, asset impairments (other than goodwill) and unusual items				$ 464	$ 79	$ 9