Pension and Other Postretirement Benefits - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 Y	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Maximum [Member]	Dec. 31, 2013 Minimum [Member]	Dec. 31, 2013 Canada [Member]	Dec. 31, 2014 Subsequent Event [Member]	Dec. 31, 2013 Pension Benefits [Member] Y	Dec. 31, 2013 Foreign Pension Plan, Defined Benefit [Member] Y	Dec. 31, 2013 10-Year Moving Average [Member] Y	Dec. 31, 2013 20-Year Moving Average [Member] Y
Defined Benefit Plan Disclosure [Line Items]
Average duration refined yield curve model parallels the plans, years	10
Percentage increase in rate of compensation								3.50%
Average period over which rate of compensation increases, years								5
Average period of historical returns used to calculate expected future returns, in years	5								4
Period of moving averages used for historical data points used to determine the expected long-term rate of return on plan assets, in years										10	20
Expected long term rate of return on plan assets	8.50%	8.50%	8.50%				8.00%
Decrease in expected long-term rate of return	0.50%
Health care cost trend rate assumed for next year	5.50%	6.00%	6.50%
Health care cost trend rate	4.50%	4.50%	5.00%	3.50%	(7.50%)
Number of years over actual annual health care cost trend experience	3
Collateral, which exceeds the value of the securities loaned				105.00%	102.00%
Cash contribution to pension plans	$ 462	$ 561	$ 336
Minimum required cash contribution to pension plan in 2014	625					90			435
Expenses related to saving and investment plans	$ 149	$ 146	$ 139