Summary of Significant Accounting Policies (Details 1) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011 MW
Utility [Member] | Entergy Arkansas [Member] | Independence Unit 1 [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Coal
Total Megawatt Capability (1)	836
Ownership	31.50%
Investment	$ 128
Accumulated Depreciation	96
Utility [Member] | Entergy Arkansas [Member] | Independence Common Facilities [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Coal
Ownership	15.75%
Investment	33
Accumulated Depreciation	24
Utility [Member] | Entergy Arkansas [Member] | White Bluff Units 1 and 2 [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Coal
Total Megawatt Capability (1)	1,659
Ownership	57.00%
Investment	494
Accumulated Depreciation	337
Utility [Member] | Entergy Arkansas [Member] | Ouachita Common Facilities [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Gas
Ownership	66.67%
Investment	171
Accumulated Depreciation	142
Utility [Member] | Entergy Gulf States Louisiana [Member] | Ouachita Common Facilities [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Gas
Ownership	33.33%
Investment	87
Accumulated Depreciation	72
Utility [Member] | Entergy Gulf States Louisiana [Member] | Roy S Nelson Unit 6 [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Coal
Total Megawatt Capability (1)	550
Ownership	40.25%
Investment	244
Accumulated Depreciation	172
Utility [Member] | Entergy Gulf States Louisiana [Member] | Roy S Nelson Unit 6 Common Facilities [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Coal
Ownership	15.92%
Investment	9
Accumulated Depreciation	3
Utility [Member] | Entergy Gulf States Louisiana [Member] | Big Cajun 2 unit 3 [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Coal
Total Megawatt Capability (1)	588
Ownership	24.15%
Investment	142
Accumulated Depreciation	97
Utility [Member] | Entergy Mississippi [Member] | Independence Units 1 and 2 and Common Facilities [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Coal
Total Megawatt Capability (1)	1,678
Ownership	25.00%
Investment	249
Accumulated Depreciation	137
Utility [Member] | Entergy Texas [Member] | Roy S Nelson Unit 6 [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Coal
Total Megawatt Capability (1)	550
Ownership	29.75%
Investment	178
Accumulated Depreciation	117
Utility [Member] | Entergy Texas [Member] | Roy S Nelson Unit 6 Common Facilities [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Coal
Ownership	11.77%
Investment	6
Accumulated Depreciation	2
Utility [Member] | Entergy Texas [Member] | Big Cajun 2 unit 3 [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Coal
Total Megawatt Capability (1)	588
Ownership	17.85%
Investment	107
Accumulated Depreciation	68
Utility [Member] | Entergy Louisiana [Member] | Acadia Common Facilities [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Gas
Ownership	50.00%
Investment	12
Accumulated Depreciation	0
Utility [Member] | System Energy [Member] | Grand Gulf Unit 1 [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Nuclear
Total Megawatt Capability (1)	1,190
Ownership	90.00%
Investment	3,929
Accumulated Depreciation	2,518
Entergy Wholesale Commodities [Member] | Independence Unit 2 [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Coal
Total Megawatt Capability (1)	842
Ownership	14.37%
Investment	68
Accumulated Depreciation	41
Entergy Wholesale Commodities [Member] | Independence Common Facilities [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Coal
Ownership	7.18%
Investment	16
Accumulated Depreciation	10
Entergy Wholesale Commodities [Member] | Roy S Nelson Unit 6 [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Coal
Total Megawatt Capability (1)	550
Ownership	10.90%
Investment	102
Accumulated Depreciation	53
Entergy Wholesale Commodities [Member] | Roy S Nelson Unit 6 Common Facilities [Member]
The subsidiaries investment and accumulated depreciation in each of the generating stations
Fuel-Type	Coal
Ownership	4.31%
Investment	2
Accumulated Depreciation	$ 1