Debt and Credit Agreements - Schedule of Issuance of Long-Term Debt (Details) - USD ($) $ in Millions	Apr. 01, 2016	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 750
Exelon Generation Co L L C [Member]
Debt Instrument [Line Items]
Interest Rate			2.74%
Exelon Generation Co L L C [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 25
Exelon Generation Co L L C [Member] | ExGen Texas Power [Member]
Debt Instrument [Line Items]
Interest Rate		5.00%
Exelon Generation Co L L C [Member] | CEU Credit Agreement [Member]
Debt Instrument [Line Items]
Interest Rate		3.19%
Exelon Generation Co L L C [Member] | Continental Wind 6000 February 28, 2033 [Member]
Debt Instrument [Line Items]
Interest Rate		6.00%
Exelon Generation Co L L C [Member] | DOE Financing Project [Member] | Energy Efficiency Project Financing [Member]
Debt Instrument [Line Items]
Interest Rate		1.43%
Debt Instrument, Face Amount		$ 32
Exelon Generation Co L L C [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Interest Rate		4.11%
Debt Instrument, Face Amount		$ 150
Baltimore Gas and Electric Company [Member]
Debt Instrument [Line Items]
Interest Rate	5.72%
Baltimore Gas and Electric Company [Member] | Convertible Debt Securities [Member]
Debt Instrument [Line Items]
Interest Rate	5.82%