Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2016

Asset Retirement Obligation Disclosure [Abstract]

Change in Asset Retirement Obligations

The following table summarizes the change in AROs. Amounts include conditional AROs.

(In thousands)		2016		2015
Balance at January 1,	$	24,360	$	19,744
Liabilities incurred(a)		1,303		2,380
Accretion expense		1,269		1,131
Liabilities settled		(110)		(124)
Revisions in estimated cash flows(a)		64		1,229
Balance at December 31,	$	26,886	$	24,360

(a)In the second quarter of 2015, MGE recorded an obligation of $2.3 million for the fair value of its legal liability for AROs associated with the effect of the final Coal Combustion Residual Rule at Columbia. An additional $1.3 million was recorded in the fourth quarter, associated with this ARO, based on revised estimates.