Schedule I - Condensed Financial Information of Parent (Exelon Corporate) - Condensed Statements of Operations and Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended										12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013		Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012
Operating Expenses [Abstract]
Operating and maintenance											$ 8,568	$ 7,270		$ 7,961
Total operating expenses											25,039	21,242		21,018
Operating Income (Loss)											3,096	3,669		2,373
Other income and (deductions)
Interest expense, net											(1,024)	(1,315)		(891)
Equity in (losses) earnings of unconsolidated affiliates											(20)	10		(91)
Other, net											455	460		353
Total other income and (deductions)											(610)	(896)		(575)
Income before income taxes											2,486	2,773		1,798
Income taxes											666	1,044		627
Net income	18	[1]	993	522	90	495	738	490	(4)	[2]	1,820	1,729		1,171
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	[3]	(317)
Comprehensive income											1,176	2,456		854
Exelon Corporate [Member]
Operating Expenses [Abstract]
Operating and maintenance											9	9		201
Operating and maintenance from affiliates											38	34		72
Other											3	12		6
Total operating expenses											50	55		279
Operating Income (Loss)											(50)	(55)		(279)
Other income and (deductions)
Interest expense, net											(237)	(116)		(153)
Equity in (losses) earnings of unconsolidated affiliates											1,779	1,903		1,278
Interest income from affiliates, net											53	36		75
Other, net											(2)	(78)		7
Total other income and (deductions)											1,593	1,745		1,207
Income before income taxes											1,543	1,690		928
Income taxes											(80)	(29)		(232)
Net income											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		(317)
Comprehensive income											$ 979	$ 2,446		$ 843

[1] Includes charges to earnings related to the impairments of certain generating assets which were held for sale and certain Upstream exploration assets. See Note 8—Impairment of Long-Lived Assets of the Combined Notes to Consolidated Financial Statements for additional information.

[2] Includes $265 million of interest expense related to the remeasurement of Exelon’s like-kind exchange tax position in the first quarter of 2013. See Note 14—Income Taxes of the Combined Notes to Consolidated Financial Statements for additional information.

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