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, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Mar. 23, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Operating Expenses [Abstract]
Operating and maintenance										$ 10,048	$ 8,322		$ 8,568
Total operating expenses										28,200	25,056		25,039
Operating Income (Loss)	$ 714	$ 1,267	$ 647	$ 483		$ 707	$ 1,200	$ 1,134	$ 1,366	3,112	4,409		3,096
Other income and (deductions)
Interest expense, net										(1,495)	(992)		(1,024)
Equity in losses of unconsolidated affiliates										(24)	(7)		0
Other, net										413	(46)		455
Total other income and (deductions)										(1,123)	(1,079)		(610)
Income before income taxes										1,989	3,330		2,486
Income taxes										761	1,073		666
Net Income										1,204	2,250		1,820
Pension and non-pension postretirement benefit plans:
Prior service benefit reclassified to periodic benefit cost, net of tax										48	46		30
Actuarial loss reclassified to periodic cost, net of tax										184	220		147
Unrealized gain (loss) on cash flow hedges, net of taxes					$ 0					2	9		(148)
Unrealized gain (loss) on marketable securities, net of taxes										(4)	(3)		8
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax										1	0		1
Unrealized gain (loss) on foreign currency translation, net of taxes										10	(21)		(9)
OtherComprehensiveIncomeLossNetOfTaxPeriodDecrease										0	0		(116)
Other comprehensive income (loss)										(36)	60	[1]	(644)
Comprehensive income										1,098	2,329		979
Exelon Corporate [Member]
Operating Expenses [Abstract]
Operating and maintenance										221	0		9
Operating and maintenance from affiliates										51	43		38
Other										4	4		3
Total operating expenses										276	47		50
Operating Income (Loss)										(276)	(47)		(50)
Other income and (deductions)
Interest expense, net										(312)	(168)		(237)
Equity in losses of unconsolidated affiliates										1,521	2,461		1,779
Interest income from affiliates, net										39	43		53
Other, net										7	(43)		(2)
Total other income and (deductions)										1,255	2,293		1,593
Income before income taxes										979	2,246		1,543
Income taxes										(155)	(23)		(80)
Net Income										1,134	2,269		1,623
Pension and non-pension postretirement benefit plans:
Prior service benefit reclassified to periodic benefit cost, net of tax										48	46		30
Actuarial loss reclassified to periodic cost, net of tax										184	220		147
Other Comprehensive Income (Loss), Finalization of Pension and Other Postretirement Benefit Plan Valuation, Net of Tax										181	99		497
Unrealized gain (loss) on cash flow hedges, net of taxes										2	9		(148)
Unrealized gain (loss) on marketable securities, net of taxes										(4)	(3)		8
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax										1	0		1
Unrealized gain (loss) on foreign currency translation, net of taxes										10	(21)		(9)
OtherComprehensiveIncomeLossNetOfTaxPeriodDecrease										0	0		116
Other comprehensive income (loss)										(36)	60		(644)
Comprehensive income										$ 1,098	$ 2,329		$ 979

[1] All amounts are net of tax and noncontrolling interests. Amounts in parenthesis represent a decrease in accumulated other comprehensive income.