Early Plant Retirements Early Plant Retirements (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Total Assets		$ 45,326	$ 42,716	$ 40,070
Asset Retirement Obligations, Noncurrent		1,063	1,024
Gain on Sale of Hudson and Mercer		54	0	0
Power [Member]
Restructuring Cost and Reserve [Line Items]
Total Assets		12,594	12,418
Asset Retirement Obligations, Noncurrent		758	810
Gain on Sale of Hudson and Mercer		54	0	0
Power [Member] | Energy Costs [Member]
Restructuring Cost and Reserve [Line Items]
Coal Inventory Lower of Cost or Market Adjustments and Capacity Penalties		3	15	62
Power [Member] | Operation and Maintenance Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			23	53
Power [Member] | Depreciation And Amortization [Member]
Restructuring Cost and Reserve [Line Items]
Depreciation, including Asset Retirement Costs			$ 964	$ 571
Nuclear Support Facilities [Member]
Restructuring Cost and Reserve [Line Items]
Public Utilities, Inventory	[1]	0
Nuclear Production, Net of Accumulated Depreciation	[1]	197
Nuclear Fuel, Net of Accumulated Depreciation	[1]	0
Public Utilities, Property, Plant and Equipment, Construction Work in Progress	[1]	5
Total Assets	[1]	202
Asset Retirement Obligations, Noncurrent	[1]	0
Liabilities	[1]	0
Net Assets	[1]	202
Peach Bottom [Member]
Restructuring Cost and Reserve [Line Items]
Public Utilities, Inventory		41
Nuclear Production, Net of Accumulated Depreciation		777
Nuclear Fuel, Net of Accumulated Depreciation		148
Public Utilities, Property, Plant and Equipment, Construction Work in Progress		20
Total Assets		986
Asset Retirement Obligations, Noncurrent		215
Liabilities		215
Net Assets		$ 771
Jointly Owned Utility Plant, Proportionate Ownership Share		50.00%
Peach Bottom [Member] | Power [Member]
Restructuring Cost and Reserve [Line Items]
Jointly Owned Utility Plant, Proportionate Ownership Share		50.00%
Salem [Member]
Restructuring Cost and Reserve [Line Items]
Public Utilities, Inventory		$ 65
Nuclear Production, Net of Accumulated Depreciation		626
Nuclear Fuel, Net of Accumulated Depreciation		110
Public Utilities, Property, Plant and Equipment, Construction Work in Progress		132
Total Assets		933
Asset Retirement Obligations, Noncurrent		240
Liabilities		240
Net Assets		$ 693
Jointly Owned Utility Plant, Proportionate Ownership Share		57.00%
Salem [Member] | Power [Member]
Restructuring Cost and Reserve [Line Items]
Jointly Owned Utility Plant, Proportionate Ownership Share		57.00%
Hope Creek [Member]
Restructuring Cost and Reserve [Line Items]
Public Utilities, Inventory		$ 84
Nuclear Production, Net of Accumulated Depreciation		635
Nuclear Fuel, Net of Accumulated Depreciation		139
Public Utilities, Property, Plant and Equipment, Construction Work in Progress		131
Total Assets		989
Asset Retirement Obligations, Noncurrent		253
Liabilities		253
Net Assets		$ 736
Jointly Owned Utility Plant, Proportionate Ownership Share		100.00%

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