Property, Plant and Equipment (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014		Dec. 31, 2013
Property Plant And Equipment [Line Items]
Less: accumulated depreciation	$ (14,369)	[1]	$ (13,713)	[2]
Property, plant and equipment, net	51,747		47,330
Property Plant And Equipment Footnotes [Abstract]
Accumulated amortization of nuclear fuel	2,411		2,371
Plant Retirement Cost [Abstract]
Inventory write down related to plant retirements	3
Exelon Generation Co L L C [Member]
Property Plant And Equipment [Line Items]
Less: accumulated depreciation	(7,397)	[1]	(7,034)	[2]
Property, plant and equipment, net	23,743		20,111
Property Plant And Equipment Footnotes [Abstract]
Accumulated amortization of nuclear fuel	2,411		2,371
Plant Retirement Cost [Abstract]
Inventory write down related to plant retirements	3
Commonwealth Edison Co [Member]
Property Plant And Equipment [Line Items]
Less: accumulated depreciation	(3,325)		(3,184)
Property, plant and equipment, net	15,121		14,666
Plant Retirement Cost [Abstract]
Inventory write down related to plant retirements	1
PECO Energy Co [Member]
Property Plant And Equipment [Line Items]
Less: accumulated depreciation	(2,969)		(2,935)
Property, plant and equipment, net	6,545		6,384
Baltimore Gas and Electric Company [Member]
Property Plant And Equipment [Line Items]
Less: accumulated depreciation	(2,781)		(2,702)
Property, plant and equipment, net	$ 6,030		$ 5,864

[1] Includes accumulated amortization of nuclear fuel in the reactor core of $2,411 million.

[2] Includes accumulated amortization of nuclear fuel in the reactor core of $2,371 million.