Consolidated Statements of Operations and Comprehensive Income (Unaudited) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Operating revenues [Abstract]
Revenues	$ 27,429	[1]	$ 24,888	[1]	$ 23,489	[1]
Operating revenues from affiliates	23		70		48
Operating expenses
Purchased power and fuel	12,472		9,468		9,121
Purchased power and fuel from affiliates	531		1,256		1,036
Operating and maintenance	8,568		7,270		7,961
Depreciation and amortization	2,314		2,153		1,881
Taxes other than income	1,154		1,095		1,019
Total operating expenses	25,039		21,242		21,018
Equity in (losses) earnings of unconsolidated affiliates	(20)		10		(91)
Gain (loss) on sales of assets	437		13		(7)
Gain on consolidation and acquisition of businesses	289		0		0
Operating Income (Loss)	3,096		3,669		2,373
Other income and (deductions)
Interest expense, net	(1,024)		(1,315)		(891)
Interest expense to affiliates, net	(41)		(41)		(37)
Other, net	455		460		353
Total other income and (deductions)	(610)		(896)		(575)
Income before income taxes	2,486		2,773		1,798
Income before income taxes	2,486		2,773		1,798
Income taxes	666		1,044		627
Net income	1,820		1,729		1,171
Net income attributable to noncontrolling interest, preferred security dividends and preference stock dividends	(197)		(10)		(11)
Net income attributable to common shareholders	1,623		1,719		1,160
Pension and non-pension postretirement benefit plans:
Prior service benefit reclassified to periodic benefit cost, net of tax	(30)		0		1
Actuarial loss reclassified to periodic cost, net of tax	147		208		168
Transition obligation reclassified to periodic cost, net of tax	0		0		2
Pension and non-pension postretirement benefit plans valuation adjustment, net of tax	(497)		669		(371)
Unrealized gain (loss) on cash flow hedges, net of taxes	(148)		(248)		(120)
Unrealized gain (loss) on marketable securities, net of taxes	1		2		2
Unrealized gain (loss) on equity investments, net of taxes	8		106		1
Unrealized gain (loss) on foreign currency translation, net of taxes	(9)		(10)		0
Reversal of CENG equity method AOCI, net of taxes	(116)		0		0
Other comprehensive income (loss)	(644)		727	[2]	(317)
Comprehensive income	1,176		2,456		854
Average shares of common stock outstanding:
Basic	860		856		816
Diluted	864		860		819
Earnings per average common share:
Basic (in usd per share)	$ 1.89		$ 2.01		$ 1.42
Diluted (in usd per share)	$ 1.88		$ 2.00		$ 1.42
Dividends per common share (in usd per share)	$ 1.24		$ 1.46		$ 2.1
Exelon Generation Co L L C [Member]
Operating revenues [Abstract]
Revenues	17,393		15,630		14,437
Operating revenues	16,614		14,207		12,735
Operating revenues from affiliates	779		1,423		1,702
Operating expenses
Purchased power and fuel	9,368		6,927		6,017
Purchased power and fuel from affiliates	557		1,270		1,044
Operating and maintenance	4,943		3,960		4,398
Operating and maintenance from affiliates	623		574		630
Depreciation and amortization	967		856		768
Taxes other than income	465		389		369
Total operating expenses	16,923		13,976		13,226
Equity in (losses) earnings of unconsolidated affiliates	(20)		10		(91)
Gain (loss) on sales of assets	437		13		(7)
Gain on consolidation and acquisition of businesses	289		0		0
Operating Income (Loss)	1,176		1,677		1,113
Other income and (deductions)
Interest expense, net	(303)		(298)		(226)
Interest expense to affiliates, net	(53)		(59)		(75)
Other, net	406		355		246
Total other income and (deductions)	50		(2)		(55)
Income before income taxes	1,226		1,675		1,058
Income taxes	207		615		500
Net income	1,019		1,060		558
Net income (loss) attributable to noncontrolling interests	184		(10)		(4)
Net income attributable to membership interest	835		1,070		562
Pension and non-pension postretirement benefit plans:
Unrealized gain (loss) on cash flow hedges, net of taxes	(132)		(398)		(403)
Unrealized gain (loss) on marketable securities, net of taxes	(1)		2		0
Unrealized gain (loss) on equity investments, net of taxes	8		107		1
Unrealized gain (loss) on foreign currency translation, net of taxes	(9)		(10)		0
Reversal of CENG equity method AOCI, net of taxes	(116)		0		0
Other comprehensive income (loss)	(250)		(299)	[2]	(402)
Comprehensive income	769		761		156
Commonwealth Edison Co [Member]
Operating revenues [Abstract]
Revenues	4,564		4,464		5,443
Operating revenues	4,560		4,461		5,441
Operating revenues from affiliates	4		3		2
Operating expenses
Purchased power and fuel	1,001		662		1,518
Purchased power from affiliate	176		512		789
Operating and maintenance	1,263		1,211		1,182
Operating and maintenance from affiliates	166		157		163
Depreciation and amortization	687		669		610
Taxes other than income	293		299		295
Total operating expenses	3,586		3,510		4,557
Equity in (losses) earnings of unconsolidated affiliates	0		0
Gain (loss) on sales of assets	2		0		0
Operating Income (Loss)	980		954		886
Other income and (deductions)
Interest expense, net	(308)		(566)		(294)
Interest expense to affiliates, net	(13)		(13)		(13)
Other, net	17		26		39
Total other income and (deductions)	(304)		(553)		(268)
Income before income taxes	676		401		618
Income taxes	268		152		239
Net income	408		249		379
Pension and non-pension postretirement benefit plans:
Unrealized gain (loss) on marketable securities, net of taxes	0		0		1
Other comprehensive income (loss)	0		0		1
Comprehensive income	408		249		380
PECO Energy Co [Member]
Operating revenues [Abstract]
Revenues	3,094		3,100		3,186
Operating revenues	3,092		3,099		3,183
Operating revenues from affiliates	2		1		3
Operating expenses
Purchased power and fuel	1,067		908		842
Purchased power from affiliate	194		392		533
Operating and maintenance	767		647		698
Operating and maintenance from affiliates	99		101		111
Depreciation and amortization	236		228		217
Taxes other than income	159		158		162
Total operating expenses	2,522		2,434		2,563
Equity in (losses) earnings of unconsolidated affiliates	0		0		0
Operating Income (Loss)	572		666		623
Other income and (deductions)
Interest expense, net	(101)		(103)		(111)
Interest expense to affiliates, net	(12)		(12)		(12)
Other, net	7		6		8
Total other income and (deductions)	(106)		(109)		(115)
Income before income taxes	466		557		508
Income taxes	114		162		127
Net income	352		395		381
Preferred security dividends and redemption	0		(7)		(4)
Net income attributable to common shareholders	352		388		377
Pension and non-pension postretirement benefit plans:
Unrealized gain (loss) on marketable securities, net of taxes	0		0		1
Other comprehensive income (loss)	0		0		1
Comprehensive income	352		395		382
Baltimore Gas and Electric Company [Member]
Operating revenues [Abstract]
Revenues	3,165		3,065		2,735
Operating revenues	3,140		3,052		2,725
Operating revenues from affiliates	25		13		10
Operating expenses
Purchased power and fuel	1,035		969		973
Purchased power from affiliate	382		452		396
Operating and maintenance	614		551		622
Operating and maintenance from affiliates	103		83		106
Depreciation and amortization	371		348		298
Taxes other than income	221		213		208
Total operating expenses	2,726		2,616		2,603
Equity in (losses) earnings of unconsolidated affiliates	0		0		0
Operating Income (Loss)	439		449		132
Other income and (deductions)
Interest expense, net	(90)		(106)		(128)
Interest expense to affiliates, net	(16)		(16)		(16)
Other, net	18		17		23
Total other income and (deductions)	(88)		(105)		(121)
Income before income taxes	351		344		11
Income taxes	140		134		7
Net income	211		210		4
Preferred security dividends and redemption	(13)		(13)		(13)
Net income attributable to common shareholders	198		197		(9)
Pension and non-pension postretirement benefit plans:
Comprehensive income	$ 211		$ 210		$ 4

[1] For the years ended December 31, 2014, 2013 and 2012, utility taxes of $89 million, $79 million and $82 million, respectively, are included in revenues and expenses for Generation. For the years ended December 31, 2014, 2013 and 2012, utility taxes of $238 million, $241 million and $239 million, respectively, are included in revenues and expenses for ComEd. For the years ended December 31, 2014, 2013 and 2012, utility taxes of $128 million, $129 million and $141 million, respectively, are included in revenues and expenses for PECO. For the years ended December 31, 2014, December 31, 2013 and for the period of March 12, 2012 through December 31, 2012, utility taxes of $86 million, $82 million and $59 million are included in revenues and expenses for BGE, respectively.

[2] All amounts are net of tax. Amounts in parenthesis represent a decrease in accumulated other comprehensive income.