Schedule I - Condensed Financial Information of Parent (Exelon Corporate) - Condensed Balance Sheet (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Current assets
Cash and cash equivalents	$ 1,878		$ 1,609		$ 1,486		$ 1,016
Accounts receivable, net
Other	1,227		1,175
Deferred income taxes	244		573
Regulatory assets	847		760
Other	865		652
Total current assets	12,097		10,137
Property, plant and equipment, net	52,087		47,330
Deferred debits and other assets
Regulatory assets	6,076		5,910
Other	1,160		964
Total deferred debits and other assets	22,630		22,457
Total assets	86,814	[1]	79,924	[1]
Current liabilities
Long-term debt due within one year	1,802		1,509
Accounts payable	3,048		2,484
Unamortized energy contract liabilities	238		261
Accrued expenses	1,539		1,633
Deferred income taxes	0		40
Regulatory liabilities	310		327
Other	1,123		858
Total current liabilities	8,762		7,728
Long-term debt	19,362		17,623
Deferred credits and other liabilities
Regulatory liabilities	4,550		4,388
Pension obligations	3,366		1,876
Non-pension postretirement benefit obligations	1,742		2,190
Other	2,147		2,540
Total deferred credits and other liabilities	33,909		30,985
Total liabilities	62,681	[1]	56,984	[1]
Shareholders’ equity
Common stock	16,709		16,741
Treasury stock, at cost (35 shares held at December 31, 2014 and 2013)	(2,327)		(2,327)
Retained earnings	10,910		10,358
Accumulated other comprehensive loss, net	(2,684)		(2,040)	[2]	(2,767)	[2]
Total shareholders’ equity	22,608		22,732
BGE preference stock not subject to mandatory redemption	193		193
Total liabilities and shareholders’ equity	86,814		79,924
Exelon Corporate [Member]
Current assets
Cash and cash equivalents	879		3		159		38
Accounts receivable, net
Other	209		72
Accounts receivable from affiliates	24		22
Deferred income taxes	20		27
Receivables from affiliates	818		179
Regulatory assets	254		233
Other	22		1
Total current assets	2,226		537
Property, plant and equipment, net	54		57
Deferred debits and other assets
Regulatory assets	3,186		3,005
Investments in affiliates	26,670		26,390
Deferred income taxes	2,187		1,890
Receivable from affiliates	943		1,522
Other	172		17
Total deferred debits and other assets	33,158		32,824
Total assets	35,438		33,418
Current liabilities
Long-term debt due within one year	1,409		10
Accounts payable	2		43
Unamortized energy contract liabilities	0		12
Accrued expenses	25		106
Deferred income taxes	60		26
Regulatory liabilities	51		2
Other	75		54
Total current liabilities	1,622		253
Long-term debt	2,841		3,033
Payables to affiliates	182		176
Deferred credits and other liabilities
Regulatory liabilities	37		43
Pension obligations	7,638		6,444
Non-pension postretirement benefit obligations	16		393
Deferred income taxes	93		70
Other	398		271
Total deferred credits and other liabilities	8,182		7,221
Total liabilities	12,827		10,683
Commitments and Contingencies
Shareholders’ equity
Common stock	16,709		16,741
Treasury stock, at cost (35 shares held at December 31, 2014 and 2013)	(2,327)		(2,327)
Retained earnings	10,910		10,358
Accumulated other comprehensive loss, net	(2,684)		(2,040)
Total shareholders’ equity	22,608		22,732
BGE preference stock not subject to mandatory redemption	3		3
Total liabilities and shareholders’ equity	$ 35,438		$ 33,418

[1] Exelon’s consolidated assets include $8,160 million and $1,755 million at December 31, 2014 and December 31, 2013, respectively, of certain VIEs that can only be used to settle the liabilities of the VIE. Exelon’s consolidated liabilities include $2,723 million and $658 million at December 31, 2014 and December 31, 2013, respectively, of certain VIEs for which the VIE creditors do not have recourse to Exelon. See Note 2–Variable Interest Entities.

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