Legal Proceedings Loss Contingencies (Details) - MPS Merchant Services, Inc. [Member] $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)
Loss Contingencies [Line Items]
Approximate amount of refunds received as a net purchaser of power through settlements with sellers of power	$ 8
Estimated additional refunds entitled to receive	$ 12
Loss Contingency, Inestimable Loss	Due to the uncertainties remaining in the case, the loss or range of loss cannot be reasonably estimated