Commitments and Contingencies, Purchased Power Agreements (Details) - Independent Power Producing Entities	9 Months Ended
Sep. 30, 2016 MW
Purchased Power Agreements [Abstract]
Generating capacity under long term purchased power agreements (in MW)	3,537
Purchase Power Agreement Expiration (Year)	2041

The expiration of purchase power agreements currently under contract (year).

No definition available.

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Balance Type:	na
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