Stock-Based Compensation Plans (Tables)

3 Months Ended

Mar. 31, 2013

Stock-Based Compensation Plans [Line Items]

Stock Based Compensation Components [Text Block]

		Three Months Ended
		March 31,
Components of Stock-Based Compensation Expense		2013		2012
Performance share awards		$	16	$	16
Stock options			1		7
Restricted stock units			20		19
Other stock-based awards			1		1
Total stock-based compensation expense included in
	operating and maintenance expense		38		43
Income tax benefit			(15)		(16)
Total after-tax stock-based compensation expense		$	23	$	27

Stock Based Compensation Expense Subsidiaries [Text Block]

	Three Months Ended
	March 31,
Subsidiaries	2013		2012
Generation	$	15	$	14
ComEd		2		5
PECO		2		3
BGE (a)		2		2
BSC (b)		17		19
Total (c)	$	38	$	43

(a)       BGE's stock-based compensation expense (pre-tax) for the three months ended March 31, 2012 includes $2 million of cost incurred prior to the closing of Exelon's merger with Constellation on March 12, 2012. This amount is not included in Exelon's stock-based compensation expense for the three months ended March 31, 2012 shown in the table titled Components of Stock-Based Compensation Expense 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 and BGE amounts above.

(c)       The stock-based compensation expense (pre-tax) for the three months ended March 31, 2013 reflects the impact of changes to the retirement eligibility requirements for employees participating in the LTIP. In addition, the stock-based compensation expense at ComEd reflects the adoption of the ComEd Key Manager Long-Term Performance Program in 2013 for certain employees, which is not consider stock-based compensation expense under the applicable authoritative guidance. In 2012, these employees participated in the Exelon Restricted Stock Award Program.