Consolidated Statements of Operations and Comprehensive Income (Unaudited) (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Prior service costs	$ 5	$ 0	$ 5	$ 1
Actuarial loss reclassified to periodic cost, taxes	(23)	(32)	(46)	(66)
Transition obligation		(1)
Pension and non-pension postretirement benefit plan valuation adjustment, taxes	(166)		(159)	(50)
Change in unrealized gain (loss) on cash flow hedges, taxes	28	45	48	77
Change in unrealized gain (loss) on equity investments taxes	77	(5)	70	(23)
Deferred Compensation Unit Valuation Adjustment tax		(6)		(6)
Actuarial loss reclassified to periodic cost, net of tax	(38)	(50)	(72)	(100)
Other Comprehensive Income (Loss), Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service (Cost) Credit, Net of Tax	(6)	0	(6)	1
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Transition (Asset) Obligation, Net of Tax		0		0
Exelon Generation Co L L C [Member]
Change in unrealized gain (loss) on cash flow hedges, taxes	25	89	44	175
Change in unrealized gain (loss) on marketable securities, taxes			(2)
Change in unrealized gain (loss) on equity investments taxes	$ 77	$ (5)	$ 70	$ (23)