Guarantees	12 Months Ended
Dec. 31, 2014
Guarantees [Abstract]
Guarantees	Guarantees In connection with the sale of its NORESCO domestic operations in December 2005, the Company agreed to maintain in place guarantees of certain warranty obligations of NORESCO. The savings guarantees provided that once the energy-efficiency construction was completed by NORESCO, the customer would experience a certain dollar amount of energy savings over a period of years. The undiscounted maximum aggregate payments that may be due related to these guarantees were approximately $153 million as of December 31, 2014, extending at a decreasing amount for approximately 13 years. In December 2014, the Company issued a $130 million performance guarantee (the Original MVP Guarantee) in connection with its subsidiary’s obligations to fund the Company’s proportionate share of the construction budget for the MVP. Upon the FERC’s initial release to begin construction of the MVP, the Original MVP Guarantee will terminate, and the Company will be obligated to issue a new guarantee in an amount equal to 33% of the subsidiary’s remaining obligations to make capital contributions to MVP LLC in connection with the then remaining construction budget. Upon the transfer of the Company’s interest in the joint venture to the Partnership, the Partnership will assume these obligations to provide performance assurances for the MVP. See Note 18 for additional discussion regarding the MVP joint venture. The NORESCO and the MVP guarantees are exempt from ASC Topic 460, Guarantees. The Company has determined that the likelihood it will be required to perform on these arrangements is remote and any potential payments are expected to be immaterial to the Company’s financial position, results of operations and liquidity. As such, the Company has not recorded any liabilities in its Consolidated Balance Sheets related to these guarantees.

Guarantees

In connection with the sale of its NORESCO domestic operations in December 2005, the Company agreed to maintain in place guarantees of certain warranty obligations of NORESCO. The savings guarantees provided that once the energy-efficiency construction was completed by NORESCO, the customer would experience a certain dollar amount of energy savings over a period of years. The undiscounted maximum aggregate payments that may be due related to these guarantees were approximately $153 million as of December 31, 2014, extending at a decreasing amount for approximately 13 years.

In December 2014, the Company issued a $130 million performance guarantee (the Original MVP Guarantee) in connection with its subsidiary’s obligations to fund the Company’s proportionate share of the construction budget for the MVP. Upon the FERC’s initial release to begin construction of the MVP, the Original MVP Guarantee will terminate, and the Company will be obligated to issue a new guarantee in an amount equal to 33% of the subsidiary’s remaining obligations to make capital contributions to MVP LLC in connection with the then remaining construction budget. Upon the transfer of the Company’s interest in the joint venture to the Partnership, the Partnership will assume these obligations to provide performance assurances for the MVP. See Note 18 for additional discussion regarding the MVP joint venture.

The NORESCO and the MVP guarantees are exempt from ASC Topic 460, Guarantees. The Company has determined that the likelihood it will be required to perform on these arrangements is remote and any potential payments are expected to be immaterial to the Company’s financial position, results of operations and liquidity. As such, the Company has not recorded any liabilities in its Consolidated Balance Sheets related to these guarantees.