Restructuring and Other Charges - Activity and Reserve Balances for Restructuring Charges (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	$ 782	$ 172	$ 281
Other layoff cost including reclassification in pension cost	185	26	58
Asset Retirement Obligations [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	58		17
Environmental Remediation [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	12		18
Pension Costs [Member]
Restructuring Cost and Reserve [Line Items]
Other layoff cost including reclassification in pension cost	$ 92