Early Plant Retirements Early Plant Retirements (Details) - USD ($) $ in Millions		3 Months Ended	9 Months Ended	12 Months Ended
		Sep. 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Early Plant Retirements [Line Items]
Total Assets		$ 41,157	$ 41,157	$ 40,070
Asset Retirement Obligations		748	748	726
Power [Member]
Early Plant Retirements [Line Items]
Total Assets		11,631	11,631	12,193
Asset Retirement Obligations		530	530	511
Power [Member] | Energy Costs [Member]
Early Plant Retirements [Line Items]
Coal Inventory Lower of Cost or Market Adjustments		1	10	62
Power [Member] | Operating Expense [Member]
Early Plant Retirements [Line Items]
Operation and Maintenance charges		8	12	53
Power [Member] | Depreciation And Amortization [Domain]
Early Plant Retirements [Line Items]
Accelerated Depreciation including Asset Retirement Costs			964	$ 571
Hope Creek [Member] | Nuclear Plant [Member]
Early Plant Retirements [Line Items]
Materials and Supplies Inventory		85	85
Nuclear Production, net of Accumulated Depreciation		452	452
Nuclear Fuel In-Service, net of Accumulated Depreciation		120	120
Construction Work in Progress (including nuclear fuel)		216	216
Total Assets		873	873
Asset Retirement Obligations		148	148
Total Liabilities		148	148
Net Assets		$ 725	$ 725
% Owned		100.00%	100.00%
Salem [Member] | Nuclear Plant [Member]
Early Plant Retirements [Line Items]
Materials and Supplies Inventory		$ 81	$ 81
Nuclear Production, net of Accumulated Depreciation		557	557
Nuclear Fuel In-Service, net of Accumulated Depreciation		94	94
Construction Work in Progress (including nuclear fuel)		130	130
Total Assets		862	862
Asset Retirement Obligations		162	162
Total Liabilities		162	162
Net Assets		$ 700	$ 700
% Owned		57.00%	57.00%
Nuclear Support Facilities [Member] | Nuclear Plant [Member]
Early Plant Retirements [Line Items]
Materials and Supplies Inventory	[1]	$ 0	$ 0
Nuclear Production, net of Accumulated Depreciation	[1]	204	204
Nuclear Fuel In-Service, net of Accumulated Depreciation	[1]	0	0
Construction Work in Progress (including nuclear fuel)	[1]	9	9
Total Assets	[1]	213	213
Asset Retirement Obligations	[1]	0	0
Total Liabilities	[1]	0	0
Net Assets	[1]	$ 213	$ 213
% Owned	[1]	0.00%	0.00%
Peach Bottom [Member] | Nuclear Plant [Member]
Early Plant Retirements [Line Items]
Materials and Supplies Inventory		$ 41	$ 41
Nuclear Production, net of Accumulated Depreciation		753	753
Nuclear Fuel In-Service, net of Accumulated Depreciation		109	109
Construction Work in Progress (including nuclear fuel)		92	92
Total Assets		995	995
Asset Retirement Obligations		164	164
Total Liabilities		164	164
Net Assets		$ 831	$ 831
% Owned		50.00%	50.00%

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