Restructuring and Other Charges - Activity and Reserve Balances for Restructuring Charges (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	$ 110	$ 244	$ 571	$ 251
Other layoff cost including reclassification in pension cost			137		185
Asset Retirement Obligations [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges			55		58
Environmental Remediation [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges			42		12
Pension Costs [Member]
Restructuring Cost and Reserve [Line Items]
Other layoff cost including reclassification in pension cost					$ 92