Actual Investment Allocations (Detail)				12 Months Ended			12 Months Ended			12 Months Ended			12 Months Ended															12 Months Ended			12 Months Ended
	Dec. 31, 2013 Pension Plans	Dec. 31, 2012 Pension Plans	Dec. 31, 2011 Pension Plans	Dec. 31, 2013 Pension Plans Equity Funds	Dec. 31, 2012 Pension Plans Equity Funds	Dec. 31, 2011 Pension Plans Equity Funds	Dec. 31, 2013 Pension Plans Fixed Income Securities	Dec. 31, 2012 Pension Plans Fixed Income Securities	Dec. 31, 2011 Pension Plans Fixed Income Securities	Dec. 31, 2013 Pension Plans Real Estate Funds	Dec. 31, 2012 Pension Plans Real Estate Funds	Dec. 31, 2011 Pension Plans Real Estate Funds	Dec. 31, 2013 Pension Plans Equity And Debt Securities		Dec. 31, 2012 Pension Plans Equity And Debt Securities		Dec. 31, 2011 Pension Plans Equity And Debt Securities		Dec. 31, 2013 Pension Plans Other		Dec. 31, 2012 Pension Plans Other		Dec. 31, 2011 Pension Plans Other		Dec. 31, 2013 Other Postretirement Benefit Plans, Defined Benefit	Dec. 31, 2012 Other Postretirement Benefit Plans, Defined Benefit	Dec. 31, 2011 Other Postretirement Benefit Plans, Defined Benefit	Dec. 31, 2013 Other Postretirement Benefit Plans, Defined Benefit Equity Funds	Dec. 31, 2012 Other Postretirement Benefit Plans, Defined Benefit Equity Funds	Dec. 31, 2011 Other Postretirement Benefit Plans, Defined Benefit Equity Funds	Dec. 31, 2013 Other Postretirement Benefit Plans, Defined Benefit Fixed Income Securities	Dec. 31, 2012 Other Postretirement Benefit Plans, Defined Benefit Fixed Income Securities	Dec. 31, 2011 Other Postretirement Benefit Plans, Defined Benefit Fixed Income Securities	Dec. 31, 2014 Scenario, Forecast Other Postretirement Benefit Plans, Defined Benefit Equity Funds	Dec. 31, 2014 Scenario, Forecast Other Postretirement Benefit Plans, Defined Benefit Fixed Income Securities
Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items]
Target Allocation				48.00%			37.00%			10.00%			5.00%															55.00%			45.00%
Actual Allocation	100.00%	100.00%	100.00%	54.00%	48.00%	49.00%	32.00%	47.00%	46.00%	1.00%	0.00%	0.00%	5.00%	[1]	5.00%	[1]	5.00%	[1]	8.00%	[2]	0.00%	[2]	0.00%	[2]	100.00%	100.00%	100.00%	57.00%	56.00%	55.00%	43.00%	44.00%	45.00%	55.00%	45.00%

[1] Represents investments in an asset allocation fund. This fund invests in both equity and debt securities.

[2] Represents investments being held in cash equivalents as of December 31, 2013 pending transfer into a Real Estate Fund.