Retirement Benefits (Tables)

3 Months Ended

Mar. 31, 2012

Retirement Benefits Tables [Abstract]

Schedule of Defined Benefit Plans Disclosures Text Block

						Other
						Postretirement
		Pension Benefits				Benefits
		Three Months Ended				Three Months Ended
		March 31,				March 31,
		2012		2011		2012		2011
Service cost		$	61	$	53	$	37	$	36
Interest cost			164		162		51		52
Expected return on assets			(232)		(235)		(29)		(28)
Amortization of:
	Transition obligation		0		0		3		2
	Prior service cost (benefit)		4		4		(3)		(9)
	Actuarial loss		106		83		19		16
Net periodic benefit cost		$	103	$	67	$	78	$	69

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

	Three Months Ended March 31,
Pension and Other Postretirement Benefit Costs		2012		2011
Generation	$	81	$	62
ComEd		69		54
PECO		13		8
BGE (a)		16		11
BSC (b)		14		12

BGE's pension and postretirement benefit costs for the three months ended March 31, 2012 and 2011 include $12 million and $11 million, respectively, 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 cost for the three months ended March 31, 2012 and 2011 shown in the first table of the Defined Benefit Pension and Other Postretirement Benefits section above.

(b)BGE's pension and postretirement benefit costs for the three months ended March 31, 2012 includes $million of cost incurred prior to the closing of the merger with Constellation on March 12, 2012. This amount is not included Exelon's net periodic benefit for the three months ended March 31, 2012 shown in the table above.

(b)       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.

Schedule Of Defined Contributions [Text Block]

	Three Months Ended March 31,
Savings Plan Matching Contributions	2012		2011
Exelon	$	16	$	16
Generation		8		8
ComEd		4		4
PECO		2		2
BGE (a)		2		2
BSC (b)		1		2

• BGE's matching contributions for the three months ended March 31, 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 three months ended March 31, 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.

• BGE's matching contributions for the three months ended March 31, 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 three months ended March 31, 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.