Drilling Plans, Agreement to Secure Drilling Rigs, Number of Agreements

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- Definition

Long Term Commitments Expense Recognized in Statements of Operations

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- Definition

Recorded Unconditional Purchase Obligation, Market Value

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- Definition

Recorded Unconditional Purchase Obligation, Time Period

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- Definition

The minimum amount the entity agreed to spend under the long-term purchase commitment.

+ References

No definition available.

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- Definition

Sets forth the number of units of goods that must be purchased within the specified time period of the agreement to avoid penalties or unfavorable effects on pricing, among other adverse consequences.

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- Definition

Specifies the time period covered by the arrangement.

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- Definition

The increase (decrease) in the period in loss contingency liabilities.

+ References

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- Definition

The estimated maximum amount of possible loss from the contingency.

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- Definition

The carrying amount of the long-term purchase obligation as of the balance sheet date, which equals the sum of all payments due.

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Commitments and Contingencies (Details) - Commitments and Agreements (USD $) In Millions, unless otherwise specified	6 Months Ended		3 Months Ended	6 Months Ended
	Jun. 30, 2012 agreements	Jun. 30, 2012 Agreement Termination	Jun. 30, 2012 Pending or threatened legal proceedings	Jun. 30, 2012 Natural Gas Alabama Gas Corporation Bcf	Jun. 30, 2012 Natural Gas, Delivery and Storage Alabama Gas Corporation	Jun. 30, 2011 Natural Gas, Delivery and Storage Alabama Gas Corporation
Long-term Purchase Commitment [Line Items]
Long-term Purchase Commitment, Amount					$ 79
Long-term Purchase Commitment, Time Period				August 2020	September 2024
Long Term Commitments Expense Recognized in Statements of Operations					25.9	25.8
Long-term Purchase Commitment, Minimum Quantity Required				180
Recorded Unconditional Purchase Obligation, Time Period				March 2013
Recorded Unconditional Purchase Obligation				2.1
Recorded Unconditional Purchase Obligation, Market Value				1.8
Drilling Plans, Agreement to Secure Drilling Rigs, Number of Agreements	3
Loss Contingency, Range of Possible Loss, Maximum		26
Loss Contingency Accrual, Carrying Value, Period Increase (Decrease)			$ 2.0