Early Plant Retirements Early Plant Retirements (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Early Plant Retirements [Line Items]
Total Assets		$ 43,707		$ 43,707		$ 42,716
Asset Retirement Obligations		1,047		1,047		1,024
Power [Member]
Early Plant Retirements [Line Items]
Total Assets		12,772		12,772		12,418
Asset Retirement Obligations		831		831		$ 810
Power [Member] | Energy Costs [Member]
Early Plant Retirements [Line Items]
Coal Inventory Lower of Cost or Market Adjustments		(1)	$ 2	3	$ 9
Power [Member] | Operation and Maintenance Expense [Member]
Early Plant Retirements [Line Items]
Restructuring Charges					4
Power [Member] | Depreciation And Amortization [Domain]
Early Plant Retirements [Line Items]
Accelerated Depreciation including Asset Retirement Costs			$ 390		$ 964
Hope Creek [Member]
Early Plant Retirements [Line Items]
Materials and Supplies Inventory		83		83
Nuclear Production, net of Accumulated Depreciation		688		688
Nuclear Fuel In-Service, net of Accumulated Depreciation		171		171
Construction Work in Progress (including nuclear fuel)		140		140
Total Assets		1,082		1,082
Asset Retirement Obligations		309		309
Total Liabilities		309		309
Net Assets		$ 773		$ 773
% Owned		100.00%		100.00%
Nuclear Support Facilities [Member]
Early Plant Retirements [Line Items]
Materials and Supplies Inventory	[1]	$ 0		$ 0
Nuclear Production, net of Accumulated Depreciation	[1]	203		203
Nuclear Fuel In-Service, net of Accumulated Depreciation	[1]	0		0
Construction Work in Progress (including nuclear fuel)	[1]	2		2
Total Assets	[1]	205		205
Asset Retirement Obligations	[1]	0		0
Total Liabilities	[1]	0		0
Net Assets	[1]	205		205
Salem [Member]
Early Plant Retirements [Line Items]
Materials and Supplies Inventory		82		82
Nuclear Production, net of Accumulated Depreciation		646		646
Nuclear Fuel In-Service, net of Accumulated Depreciation		89		89
Construction Work in Progress (including nuclear fuel)		105		105
Total Assets		922		922
Asset Retirement Obligations		255		255
Total Liabilities		255		255
Net Assets		$ 667		$ 667
% Owned		57.00%		57.00%
Peach Bottom [Member]
Early Plant Retirements [Line Items]
Materials and Supplies Inventory		$ 42		$ 42
Nuclear Production, net of Accumulated Depreciation		786		786
Nuclear Fuel In-Service, net of Accumulated Depreciation		119		119
Construction Work in Progress (including nuclear fuel)		24		24
Total Assets		971		971
Asset Retirement Obligations		210		210
Total Liabilities		210		210
Net Assets		$ 761		$ 761
% Owned		50.00%		50.00%

[1] Includes Hope Creek’s and Salem’s shared support facilities and other nuclear development capital.