Retirement Benefits (Tables)

9 Months Ended

Sep. 30, 2013

Retirement Benefits [Line Items]

Schedule of Defined Benefit Plans Disclosures [Text Block]

			Pension Benefits				Other Postretirement Benefits
			Three Months Ended				Three Months Ended
			September 30,				September 30,
			2013		2012		2013		2012
Service cost		$	79	$	76	$	41	$	38
Interest cost			163		181		48		53
Expected return on assets			(253)		(258)		(33)		(28)
Amortization of:
	Transition obligation		0		0		0		2
	Prior service cost (benefit)		3		5		(4)		(3)
	Actuarial loss		140		117		20		19
Settlement charges			9		9		0		0
Curtailment gain			0		0		0		(5)
Net periodic benefit cost		$	141	$	130	$	72	$	76
			Pension Benefits				Other Postretirement Benefits
			Nine Months Ended				Nine Months Ended
			September 30,				September 30,
			2013		2012		2013		2012
Service cost		$	238	$	211	$	122	$	114
Interest cost			488		524		145		157
Expected return on assets			(761)		(742)		(99)		(86)
Amortization of:
	Transition obligation		0		0		0		8
	Prior service cost (benefit)		10		12		(14)		(10)
	Actuarial loss		421		338		62		58
Settlement charges			9		9		0		0
Contractual termination benefit cost (a)			0		14		0		6
Curtailment gain			0		0		0		(7)
Net periodic benefit cost		$	405	$	366	$	216	$	240

• ComEd and BGE established regulatory assets of $1 million and $4 million, respectively, for their portion of the second quarter 2012 contractual termination benefit charge.

Schedule Of Pension And Other Postretirement Benefit Costs [Text Block]

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
Pension and Other Postretirement Benefit Costs	2013		2012		2013		2012
Generation	$	87	$	85	$	259	$	259
ComEd		77		75		231		212
PECO		11		12		32		38
BGE (a)(b)		14		14		41		46
BSC (c)		24		20		58		63

(b)       BGE's pension and other postretirement benefit costs for the three and nine months ended September 30, 2012 includes a $3 million contractual termination benefit charge, which was recorded as a regulatory asset as of September 30, 2012.

BGE's pension and postretirement benefit costs for the nine months ended September 30, 2012include $12 million of costs incurred prior to the closing of Exelon's merger with Constellation on March 12, 2012.These amounts are not included in Exelon's net periodic benefit costs for the ninemonths ended September 30, 2012shown in the first table of the Defined Benefit Pension and Other Postretirement Benefits section above.

These amounts primarily represent amounts billed to Exelon's subsidiaries through intercompany allocations. These amounts are not included in the Generation, ComEd, PECO or BGE amounts above.As of September 30, 2012, ComEd and BGE each recorded a regulatory asset of $1 million related to their BSC-billed portion of the second quarter 2012 contractual termination benefit charge.

Schedule Of Defined Contributions [Text Block]

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
Savings Plan Matching Contributions	2013		2012		2013		2012
Exelon	$	18	$	19	$	61	$	55
Generation		8		9		29		25
ComEd		6		5		16		14
PECO		2		2		6		5
BGE (a)		1		1		5		5
BSC (b)		1		2		5		6

• BGE's matching contributions for the nine months ended September 30, 2012 include $1 million of costs incurred prior to the closing of Exelon's merger with Constellation on March 12, 2012, which is not included in Exelon's matching contributions for the nine months ended September 30, 2012.
• These amounts primarily represent amounts billed to Exelon's subsidiaries through intercompany allocations. These costs are not included in the Generation, ComEd, PECO or BGE amounts above.