Consolidated Statements of Operations and Comprehensive Income (Unaudited) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating revenues [Abstract]
Operating revenues from affiliates		$ 48	$ 9
Revenues	24,888	23,489	19,063
Operating expenses
Purchased power	9,468	9,121	7,130
Operating and maintenance	7,270	7,961	5,184
Operating and maintenance for regulatory required programs
Depreciation and amortization	2,153	1,881	1,347
Taxes other than income	1,095	1,019	785
Total operating expenses	21,242	21,018	14,583
Loss on equity method investments	10	(91)	(1)
Operating income	3,656	2,380	4,479
Other income and deductions
Interest expense	(1,315)	(891)	(701)
Interest expense to affiliates, net	(41)	(37)	(25)
Other, net	473	346	203
Total other income and deductions	(883)	(582)	(523)
Income before income taxes	2,773	1,798	3,956
Income taxes	1,044	627	1,457
Income from continuing operations
Discontinued operations
Income from discontinued operations, net
Net income	1,729	1,171	2,499
Net income (loss) attributable to noncontrolling interests and preferred security dividends	(10)	(11)	(4)
Net income on common stock	1,719	1,160	2,495
Pension and non-pension postretirement benefit plans:
Prior service benefit reclassified to periodic benefit cost, net of tax	0	(1)	5
Actuarial loss reclassified to periodic cost, net of tax	(208)	(168)	(136)
Transition obligation reclassified to periodic cost, net of tax	0	(2)	(4)
Pension and non-pension postretirement benefit plans valuation adjustment	669	(371)	(250)
Change in unrealized gain (loss) on cash-flow hedges	(248)	(120)	88
Change in unrealized income (loss) on equity investments	106	1	0
Change in unrealized income (loss) on foreign currency translation	(10)	0	0
Change in unrealized gain (loss) on marketable securities	2	2	0
Other comprehensive income (loss)	727	(317)	(27)
Comprehensive income	2,456	854	2,472
Average shares of common stock outstanding:
Basic	856	816	663
Diluted	860	819	665
Earnings per average common share - basic
Income from continuing operations	$ 2.01	$ 1.42	$ 3.76
Earnings per average common share - diluted
Net income	$ 2.00	$ 1.42	$ 3.75
Dividends per common share	$ 1.46	$ 2.10	$ 2.10
Exelon Generation Co L L C [Member]
Operating revenues [Abstract]
Operating revenues	14,207	12,735	9,286
Operating revenues from affiliates	1,423	1,702	1,161
Revenues	15,630	14,437	10,447
Operating expenses
Purchased power and fuel from affiliate	1,270	1,044	138
Purchased power	6,927	6,017	3,451
Operating and maintenance	3,960	4,398	2,827
Operating and maintenance from affiliate	574	630	321
Depreciation and amortization	856	768	570
Taxes other than income	389	369	264
Total operating expenses	13,976	13,226	7,571
Loss on equity method investments	10	(91)	(1)
Operating income	1,664	1,120	2,875
Other income and deductions
Interest expense	(298)	(226)	(170)
Interest expense to affiliates, net	(59)	(75)
Other, net	368	239	122
Total other income and deductions	11	(62)	(48)
Income before income taxes	1,675	1,058	2,827
Income taxes	615	500	1,056
Discontinued operations
Net income	1,060	558	1,771
Income (Loss) attributable to noncontrolling interest	10	4
Net income on membership interest	1,070	562	1,771
Pension and non-pension postretirement benefit plans:
Change in unrealized gain (loss) on cash-flow hedges	(398)	(403)	(98)
Change in unrealized income (loss) on equity investments	107	1
Change in unrealized income (loss) on foreign currency translation	(10)
Change in unrealized gain (loss) on marketable securities	2
Other comprehensive income (loss)	(299)	(402)	(98)
Comprehensive income	761	156	1,673
Commonwealth Edison Co [Member]
Operating revenues [Abstract]
Operating revenues	4,461	5,441	6,054
Operating revenues from affiliates	3	2	2
Revenues	4,464	5,443	6,056
Operating expenses
Purchased power	662	1,518	2,382
Purchased power from affiliate	512	789	653
Operating and maintenance	1,211	1,182	1,031
Operating and maintenance from affiliate	157	163	158
Depreciation and amortization	669	610	554
Taxes other than income	299	295	296
Total operating expenses	3,510	4,557	5,074
Loss on equity method investments	0	0	0
Operating income	954	886	982
Other income and deductions
Interest expense	(566)	(294)	(330)
Interest expense to affiliates, net	(13)	(13)	(15)
Other, net	26	39	29
Total other income and deductions	(553)	(268)	(316)
Income before income taxes	401	618	666
Income taxes	152	239	250
Discontinued operations
Net income	249	379	416
Pension and non-pension postretirement benefit plans:
Change in unrealized gain (loss) on marketable securities	0	1	0
Other comprehensive income (loss)	0	1	0
Comprehensive income	249	380	416
PECO Energy Co [Member]
Operating revenues [Abstract]
Operating revenues	3,099	3,183	3,715
Operating revenues from affiliates	1	3	5
Revenues	3,100	3,186	3,720
Operating expenses
Purchased power	908	842	1,369
Purchased power from affiliate	392	533	495
Operating and maintenance	647	698	698
Operating and maintenance from affiliate	101	111	96
Depreciation and amortization	228	217	202
Taxes other than income	158	162	205
Total operating expenses	2,434	2,563	3,065
Operating income	666	623	655
Other income and deductions
Interest expense	(103)	(111)	(122)
Interest expense to affiliates, net	(12)	(12)	(12)
Other, net	6	8	14
Total other income and deductions	(109)	(115)	(120)
Income before income taxes	557	508	535
Income taxes	162	127	146
Discontinued operations
Net income	395	381	389
Preferred security dividends	(7)	(4)	(4)
Net income on common stock	388	377	385
Pension and non-pension postretirement benefit plans:
Change in unrealized gain (loss) on marketable securities	0	1	0
Other comprehensive income (loss)	0	1	0
Comprehensive income	395	382	389
Baltimore Gas and Electric Company [Member]
Operating revenues [Abstract]
Operating revenues	3,052	2,725	3,060
Operating revenues from affiliates	13	10	8
Revenues	3,065	2,735	3,068
Operating expenses
Purchased power and fuel	969	973	1,245
Purchased power from affiliate	452	396	348
Operating and maintenance	551	622	530
Operating and maintenance from affiliate	83	106	150
Depreciation and amortization	348	298	274
Taxes other than income	213	208	207
Total operating expenses	2,616	2,603	2,754
Operating income	449	132	314
Other income and deductions
Interest expense	(106)	(128)	(113)
Interest expense to affiliates, net	(16)	(16)	(16)
Other, net	17	23	26
Total other income and deductions	(105)	(121)	(103)
Income before income taxes	344	11	211
Income taxes	134	7	75
Discontinued operations
Net income	210	4	136
Preferred security dividends	(13)	(13)	(13)
Net income on common stock	197	(9)	123
Pension and non-pension postretirement benefit plans:
Comprehensive income	$ 210	$ 4	$ 136