Income Tax	6 Months Ended
Income Tax	Jun. 30, 2015
Income Tax Examination [Line Items]
Income Tax	Income Tax Con Edison’s income tax expense decreased to $101 million for the three months ended June 30, 2015 from $102 million for the three months ended June 30, 2014. Con Edison's effective tax rate for the three months ended June 30, 2015 and 2014 was 32 percent. CECONY’s income tax expense increased to $101 million for the three months ended June 30, 2015 from $78 million for the three months ended June 30, 2014. CECONY's effective tax rate for the three months ended June 30, 2015 and 2014 was 32 percent and 31 percent, respectively. The increase in CECONY’s effective tax rate is due primarily to plant-related flow through items and lower injuries and damages claims in 2015, partially offset by lower amortization of New York State’s Metropolitan Transportation Authority business tax. Con Edison’s income tax expense was $300 million for the six months ended June 30, 2015 and 2014. Con Edison's effective tax rate for the six months ended June 30, 2015 and 2014 was 34 percent. CECONY’s income tax expense increased to $293 million for the six months ended June 30, 2015 from $262 million for the six months ended June 30, 2014. CECONY's effective tax rate for the six months ended June 30, 2015 and 2014 was 34 percent. Uncertain Tax Positions At June 30, 2015 the estimated liability for uncertain tax positions for Con Edison was $34 million ($2 million for CECONY). Con Edison reasonably expects to resolve approximately $25 million ($16 million, net of federal taxes) of its uncertain tax positions within the next twelve months, of which the entire amount, if recognized, would reduce Con Edison’s effective tax rate. The amount related to CECONY is approximately $2 million ($1 million, net of federal taxes), of which the entire amount, if recognized, would reduce CECONY’s effective tax rate. The total amount of unrecognized tax benefits, if recognized, that would reduce Con Edison’s effective tax rate is $34 million ($22 million, net of federal taxes). The Companies recognize interest on liabilities for uncertain tax positions in interest expense and would recognize penalties, if any, in operating expenses in the Companies’ consolidated income statements. In the three and six months ended June 30, 2015, Con Edison recognized an immaterial amount of interest expense and no penalties for uncertain tax positions in its consolidated income statements. At June 30, 2015 and December 31, 2014, Con Edison recognized an immaterial amount of accrued interest on its consolidated balance sheets.
CECONY
Income Tax Examination [Line Items]
Income Tax	Income Tax Con Edison’s income tax expense decreased to $101 million for the three months ended June 30, 2015 from $102 million for the three months ended June 30, 2014. Con Edison's effective tax rate for the three months ended June 30, 2015 and 2014 was 32 percent. CECONY’s income tax expense increased to $101 million for the three months ended June 30, 2015 from $78 million for the three months ended June 30, 2014. CECONY's effective tax rate for the three months ended June 30, 2015 and 2014 was 32 percent and 31 percent, respectively. The increase in CECONY’s effective tax rate is due primarily to plant-related flow through items and lower injuries and damages claims in 2015, partially offset by lower amortization of New York State’s Metropolitan Transportation Authority business tax. Con Edison’s income tax expense was $300 million for the six months ended June 30, 2015 and 2014. Con Edison's effective tax rate for the six months ended June 30, 2015 and 2014 was 34 percent. CECONY’s income tax expense increased to $293 million for the six months ended June 30, 2015 from $262 million for the six months ended June 30, 2014. CECONY's effective tax rate for the six months ended June 30, 2015 and 2014 was 34 percent. Uncertain Tax Positions At June 30, 2015 the estimated liability for uncertain tax positions for Con Edison was $34 million ($2 million for CECONY). Con Edison reasonably expects to resolve approximately $25 million ($16 million, net of federal taxes) of its uncertain tax positions within the next twelve months, of which the entire amount, if recognized, would reduce Con Edison’s effective tax rate. The amount related to CECONY is approximately $2 million ($1 million, net of federal taxes), of which the entire amount, if recognized, would reduce CECONY’s effective tax rate. The total amount of unrecognized tax benefits, if recognized, that would reduce Con Edison’s effective tax rate is $34 million ($22 million, net of federal taxes). The Companies recognize interest on liabilities for uncertain tax positions in interest expense and would recognize penalties, if any, in operating expenses in the Companies’ consolidated income statements. In the three and six months ended June 30, 2015, Con Edison recognized an immaterial amount of interest expense and no penalties for uncertain tax positions in its consolidated income statements. At June 30, 2015 and December 31, 2014, Con Edison recognized an immaterial amount of accrued interest on its consolidated balance sheets.