Exhibit 12.3

Commonwealth Edison Company

Ratio of Earnings to Fixed Charges

	Years Ended December 31,
	2009			2010			2011			2012			2013
Pre-tax income from continuing operations		602			693			666			618			401
Plus: Loss from equity investees		—			—			—			—			—
Less: Capitalized interest		(3	)		(2	)		(4	)		(3	)		(5	)
Pre-tax income from continuing operations after adjustment for income or loss from equity investees and capitalized interest		599			691			662			615			396
Fixed Charges:
Interest expensed and capitalized, amortization of debt discount and premium on all indebtedness (a)		301			368			330			297			575
Interest component of rental expense (b)		7			6			6			6			5
Total fixed charges		308			374			336			303			580
Pre-tax income from continuing operations after adjustment for income or loss from equity investees, capitalized interest plus fixed charges		907			1,065			998			918			976
Ratio of earnings to fixed charges		2.9			2.8			3.0			3.0			1.7

(a) Represents one-third of rental expense relating to operating leases, which is a reasonable approximation of the interest factor.

(b) Includes interest expense of $294 million for the year ended December 31, 2013, related to the remeasurement of the like-kind exchange tax position. See Note 14 — Income taxes of the Exelon Form 10-K for the year ended December 31, 2013, for additional information regarding the like-kind exchange tax position.