Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) shares in Millions, $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Accumulated depreciation and amortization	$ 24,449	$ 23,979
Common Stock, Shares Authorized	2,000	2,000
Common Stock, Shares, Outstanding	974	973
Treasury Stock, Shares held	2	2
Exelon Generation Co L L C [Member]
Accumulated depreciation and amortization	$ 12,114	$ 12,017
Commonwealth Edison Co [Member]
Accumulated depreciation and amortization	5,315	5,168
PECO Energy Co [Member]
Accumulated depreciation and amortization	3,753	3,718
Baltimore Gas and Electric Company [Member]
Accumulated depreciation and amortization	3,898	3,834
Pepco Holdings LLC [Member]
Accumulated depreciation and amortization	1,319	1,213
Potomac Electric Power Company [Member]
Accumulated depreciation and amortization	3,561	3,517
Delmarva Power and Light Company [Member]
Accumulated depreciation and amortization	1,452	1,425
Atlantic City Electric Company [Member]
Accumulated depreciation and amortization	$ 1,236	$ 1,210

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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