Merger (Details 3) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Total intangible assets recorded
Intangible assets	$ 973	$ 256
NUG | Purchase contract assets
Total intangible assets recorded
Intangible assets	198
Purchase contract assets
Total intangible assets recorded
Intangible assets	252
Purchase contract assets | OVEC
Total intangible assets recorded
Intangible assets	54
Energy contracts | Intangible Assets
Total intangible assets recorded
Intangible assets	105
Coal contracts | Intangible Assets
Total intangible assets recorded
Intangible assets	487
Intangible Assets
Total intangible assets recorded
Intangible assets	721
Intangible Assets | FES customer intangible assets
Total intangible assets recorded
Intangible assets	$ 129