Other Material Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended			12 Months Ended
	Jul. 31, 2007 Person	Dec. 31, 2013 Lawsuits	Dec. 31, 2012	Dec. 31, 2013 Con Edison Development [Member]	Dec. 31, 2013 Construction and Operation of Solar Energy Facilities [Member]	Dec. 31, 2013 Other [Member]	Dec. 31, 2013 Insurance Receivable [Member]
Operating Leased Assets [Line Items]
Number of person died in steam ruptured	1
Number of suits pending against the company		90
Estimated accrued liability for suits							$ 50
Insurance receivable for suits		50
Guarantee obligations maximum exposure		1,331	859	80		31
Percentage of variable interests				50.00%
Guarantees issued					3
Estimate of maximum potential obligation						5
Indemnity agreements amount						$ 25