Property, Plant and Equipment - Annual Depreciation Provisions as Percentage of Average Service Life (Details)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Electric Transmission and Distribution Equipment [Member]
Property, Plant and Equipment [Line Items]
Annual depreciation rate	2.83%	2.93%	2.91%
Electric Generation Equipment [Member]
Property, Plant and Equipment [Line Items]
Annual depreciation rate	3.47%	3.50%	3.35%
Gas Distribution Equipment [Member]
Property, Plant and Equipment [Line Items]
Annual depreciation rate	2.17%	2.13%	2.06%
Common Electric And Gas T And D Equipment [Member]
Property, Plant and Equipment [Line Items]
Annual depreciation rate	7.79%	7.32%	7.53%
PECO Energy Co [Member] | Electric Transmission and Distribution Equipment [Member]
Property, Plant and Equipment [Line Items]
Annual depreciation rate	2.39%	2.55%	2.73%
PECO Energy Co [Member] | Gas Distribution Equipment [Member]
Property, Plant and Equipment [Line Items]
Annual depreciation rate	1.87%	1.84%	1.79%
PECO Energy Co [Member] | Common Electric And Gas T And D Equipment [Member]
Property, Plant and Equipment [Line Items]
Annual depreciation rate	5.16%	5.16%	6.65%
Baltimore Gas and Electric Company [Member] | Electric Transmission and Distribution Equipment [Member]
Property, Plant and Equipment [Line Items]
Annual depreciation rate	2.62%	2.96%	2.91%
Baltimore Gas and Electric Company [Member] | Gas Distribution Equipment [Member]
Property, Plant and Equipment [Line Items]
Annual depreciation rate	2.50%	2.47%	2.36%
Baltimore Gas and Electric Company [Member] | Common Electric And Gas T And D Equipment [Member]
Property, Plant and Equipment [Line Items]
Annual depreciation rate	10.35%	9.49%	8.45%