Quarterly Data (Tables)

12 Months Ended

Dec. 31, 2013

Quarterly Financial Data [Line Items]

Quarterly Financial Information Table [Text Block]

									Net (Loss) Income
									on Common
	Operating Revenues				Operating Income				Stock
	2013		2012		2013		2012		2013		2012
Quarter ended:
March 31	$	6,082	$	4,690	$	508	$	359	$	(4)	$	200
June 30		6,141		5,966		1,005		714		490		286
September 30		6,502		6,579		1,254		603		738		296
December 31		6,163		6,254		889		704		495		378

Average Basic And Diluted Shares And Net Income Per Basic And Diluted Share [Text Block]

	Average Basic Shares
	Outstanding				Net (Loss) Income
	(in millions)				per Basic Share
	2013		2012		2013		2012
Quarter ended:
March 31		855		705	$	(0.01)	$	0.28
June 30		856		853		0.57		0.34
September 30		857		854		0.86		0.35
December 31		856		854		0.60		0.44
	Average Diluted Shares
	Outstanding				Net (Loss) Income
	(in millions)				per Diluted Share
	2013		2012		2013		2012
Quarter ended:
March 31		855		707	$	(0.01)	$	0.28
June 30		860		856		0.57		0.33
September 30		860		857		0.86		0.35
December 31		860		857		0.59		0.44

Per Share Information [Text Block]

	2013								2012
	Fourth		Third		Second		First		Fourth		Third		Second		First
	Quarter		Quarter		Quarter		Quarter		Quarter		Quarter		Quarter		Quarter
High price	$	30.59	$	32.42	$	37.80	$	34.56	$	37.50	$	39.82	$	39.37	$	43.70
Low price		26.64		29.42		29.84		29.10		28.40		34.54		36.27		38.31
Close		27.39		29.64		30.88		34.48		29.74		35.58		37.62		39.21
Dividends		0.310		0.310		0.310		0.525		0.525		0.525		0.525		0.525

Exelon Generation Co L L C [Member]

Quarterly Financial Data [Line Items]

Quarterly Financial Information Table [Text Block]

									Net (Loss) Income
									on Membership
	Operating Revenues				Operating (Loss) Income				Interest
	2013		2012		2013		2012		2013		2012
Quarter ended:
March 31	$	3,533	$	2,743	$	(64)	$	272	$	(18)	$	168
June 30		4,070		3,765		603		384		330		166
September 30		4,255		4,031		721		174		490		91
December 31		3,772		3,898		405		290		269		137

Commonwealth Edison Co [Member]

Quarterly Financial Data [Line Items]

Quarterly Financial Information Table [Text Block]

	Operating Revenues				Operating Income				Net (Loss) Income
	2013		2012		2013		2012		2013		2012
Quarter ended:
March 31	$	1,160	$	1,388	$	209	$	226	$	(81)	$	87
June 30		1,080		1,281		232		142		96		42
September 30		1,156		1,484		278		218		126		90
December 31		1,068		1,290		236		300		109		160

PECO Energy Co [Member]

Quarterly Financial Data [Line Items]

Quarterly Financial Information Table [Text Block]

									Net Income
									on Common
	Operating Revenues				Operating Income				Stock
	2013		2012		2013		2012		2013		2012
Quarter ended:
March 31	$	895	$	875	$	203	$	177	$	121	$	96
June 30		672		715		138		151		72		79
September 30		728		806		155		178		92		122
December 31		805		790		168		117		102		79

Baltimore Gas and Electric Company [Member]

Quarterly Financial Data [Line Items]

Quarterly Financial Information Table [Text Block]

									Net Income (Loss)
					Operating				attributable to
	Operating Revenues				Income (Loss)				Common Shareholders
	2013		2012		2013		2012		2013		2012
Quarter ended:
March 31	$	880	$	697	$	163	$	(11)	$	77	$	(33)
June 30		653		616		69		52		22		13
September 30		737		720		114		30		50		(4)
December 31		794		703		101		61		47		15