Early Plant Retirements Early Plant Retirements (Details) - USD ($) $ in Millions		3 Months Ended	6 Months Ended	12 Months Ended
		Jun. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Early Plant Retirements [Line Items]
Total Assets		$ 40,524	$ 40,524	$ 40,070
Asset Retirement Obligations		744	744	726
Power [Member]
Early Plant Retirements [Line Items]
Total Assets		11,619	11,619	12,193
Asset Retirement Obligations		526	526	511
Power [Member] | Energy Costs [Member]
Early Plant Retirements [Line Items]
Coal Inventory Lower of Cost or Market Adjustments		2	9	62
Power [Member] | Operating Expense [Member]
Early Plant Retirements [Line Items]
Operation and Maintenance charges		4	4	53
Power [Member] | Depreciation And Amortization [Domain]
Early Plant Retirements [Line Items]
Accelerated Depreciation including Asset Retirement Costs		390	964	$ 571
Hope Creek [Member] | Nuclear Plant [Member]
Early Plant Retirements [Line Items]
Materials and Supplies Inventory		83	83
Nuclear Production, net of Accumulated Depreciation		453	453
Nuclear Fuel In-Service, net of Accumulated Depreciation		136	136
Construction Work in Progress (including nuclear fuel)		168	168
Total Assets		840	840
Asset Retirement Obligations		146	146
Total Liabilities		146	146
Net Assets		$ 694	$ 694
% Owned		100.00%	100.00%
Salem [Member] | Nuclear Plant [Member]
Early Plant Retirements [Line Items]
Materials and Supplies Inventory		$ 80	$ 80
Nuclear Production, net of Accumulated Depreciation		561	561
Nuclear Fuel In-Service, net of Accumulated Depreciation		113	113
Construction Work in Progress (including nuclear fuel)		109	109
Total Assets		863	863
Asset Retirement Obligations		159	159
Total Liabilities		159	159
Net Assets		$ 704	$ 704
% 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]	208	208
Nuclear Fuel In-Service, net of Accumulated Depreciation	[1]	0	0
Construction Work in Progress (including nuclear fuel)	[1]	9	9
Total Assets	[1]	217	217
Asset Retirement Obligations	[1]	0	0
Total Liabilities	[1]	0	0
Net Assets	[1]	$ 217	$ 217
% 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		758	758
Nuclear Fuel In-Service, net of Accumulated Depreciation		125	125
Construction Work in Progress (including nuclear fuel)		31	31
Total Assets		955	955
Asset Retirement Obligations		162	162
Total Liabilities		162	162
Net Assets		$ 793	$ 793
% Owned		50.00%	50.00%

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