Schedule I - Condensed Financial Information of Parent (Exelon Corporate) - Condensed Statements of Operations and Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended										12 Months Ended
	Dec. 31, 2015	[1]	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	[2]	Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013
Operating Expenses [Abstract]
Operating and maintenance											$ 8,322	$ 8,568		$ 7,270
Total operating expenses											25,056	25,039		21,242
Operating Income (Loss)											4,409	3,096		3,669
Other income and (deductions)
Interest expense, net											(992)	(1,024)		(1,315)
Equity in (losses) earnings of unconsolidated affiliates												(20)		10
Other, net											(46)	455		460
Total other income and (deductions)											(1,079)	(610)		(896)
Income before income taxes											3,330	2,486		2,773
Income taxes											1,073	666		1,044
Net income	$ 309		$ 629	$ 638	$ 693	$ 18	$ 993	$ 522	$ 90		2,250	1,820		1,729
Pension and non-pension postretirement benefit plans:
Prior service benefit reclassified to periodic benefit cost, net of tax											46	30		0
Actuarial loss reclassified to periodic cost, net of tax											220	147		208
Pension and non-pension postretirement benefit plans valuation adjustment, net of tax											(99)	(497)		669
Unrealized gain (loss) on cash flow hedges, net of taxes											9	(148)		(248)
Unrealized gain (loss) on marketable securities, net of taxes											0	1		2
Unrealized gain (loss) on equity investments, net of taxes											(3)	8		106
Unrealized gain (loss) on foreign currency translation, net of taxes											(21)	(9)		(10)
Reversal of CENG equity method AOCI, net of taxes											0	(116)		0
Other comprehensive income (loss)											60	(644)	[3]	727
Comprehensive income											2,310	1,176		2,456
Exelon Corporate [Member]
Operating Expenses [Abstract]
Operating and maintenance											0	9		9
Operating and maintenance from affiliates											43	38		34
Other											4	3		12
Total operating expenses											47	50		55
Operating Income (Loss)											(47)	(50)		(55)
Other income and (deductions)
Interest expense, net											(168)	(237)		(116)
Equity in (losses) earnings of unconsolidated affiliates											2,461	1,779		1,903
Interest income from affiliates, net											43	53		36
Other, net											(43)	(2)		(78)
Total other income and (deductions)											2,293	1,593		1,745
Income before income taxes											2,246	1,543		1,690
Income taxes											(23)	(80)		(29)
Net income											2,269	1,623		1,719
Pension and non-pension postretirement benefit plans:
Prior service benefit reclassified to periodic benefit cost, net of tax											46	30		0
Actuarial loss reclassified to periodic cost, net of tax											220	147		208
Transition obligation reclassified to periodic cost, net of tax											0	0		0
Pension and non-pension postretirement benefit plans valuation adjustment, net of tax											(99)	(497)		669
Unrealized gain (loss) on cash flow hedges, net of taxes											9	(148)		(248)
Unrealized gain (loss) on marketable securities, net of taxes											0	1		2
Unrealized gain (loss) on equity investments, net of taxes											(3)	8		106
Unrealized gain (loss) on foreign currency translation, net of taxes											(21)	(9)		(10)
Reversal of CENG equity method AOCI, net of taxes											0
Other comprehensive income (loss)											60	(644)		727
Comprehensive income											$ 2,329	$ 979		$ 2,446

[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] {F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOmJiZTkxZGVlYTU0NDQzYzU5MmI5ODA2YTIzODFjMGRkfFRleHRTZWxlY3Rpb246NEExNTZFREE4NkYwMUZCQUZDQTExMjI1RThCRDM3QzcM}

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