Property, Plant, And Equipment (Significant Unobservable Inputs) (Table)	Mar. 31, 2012
Operating Margin Used in Asset Valuation	7.20%
Weighted Average Cost of Capital Used In Asset Valuation	7.80%
Maximum [Member]
Operating Margin Used in Asset Valuation Range	7.80%
Weighted Average Cost of Capital Used in Asset Valuation Range	8.00%
Minimum [Member]
Operating Margin Used in Asset Valuation Range	6.10%
Weighted Average Cost of Capital Used in Asset Valuation Range	7.50%