Regulatory Assets and Liabilities

The following table summarizes the individual components of unamortized regulatory assets and liabilities as of December 31:



	Estimated Recovery Period	*	2016		2015
			(In thousands)
Regulatory assets:
Pension and postretirement benefits (a)	(e)		$	176,025	$	185,832
Taxes recoverable from customers (a)	Over plant lives		28,278		27,682
Manufactured gas plant sites remediation (a)	—		18,259		18,617
Asset retirement obligations (a)	—		42,580		8,000
Natural gas costs recoverable through rate adjustments (b)	Up to 1 year		2,242		547
Long-term debt refinancing costs (a)	Up to 21 years		6,248		7,031
Costs related to identifying generation development (a)	Up to 10 years		3,407		3,808
Other (a) (b)	Largely within 1- 4 years		30,281		11,741
Total regulatory assets			307,320		263,258
Regulatory liabilities:
Plant removal and decommissioning costs (c)			176,972		182,981
Taxes refundable to customers (c)			11,010		17,060
Pension and postretirement benefits (c)			9,099		4,764
Natural gas costs refundable through rate adjustments (d)			25,580		20,884
Other (c) (d)			19,191		17,429
Total regulatory liabilities			241,852		243,118
Net regulatory position			$	65,468	$	20,140


*	Estimated recovery period for regulatory assets currently being recovered in rates charged to customers.


(a)	Included in deferred charges and other assets - other on the Consolidated Balance Sheets.


(b)	Included in prepayments and other current assets on the Consolidated Balance Sheets.


(c)	Included in deferred credits and other liabilities - other on the Consolidated Balance Sheets.


(d)	Included in other accrued liabilities on the Consolidated Balance Sheets.


(e)	Recovered as expense is incurred or cash contributions are made.

The regulatory assets are expected to be recovered in rates charged to customers. A portion of the Company's regulatory assets are not earning a return; however, these regulatory assets are expected to be recovered from customers in future rates. As of December 31, 2016 and 2015, approximately $255.4 million and $224.7 million, respectively, of regulatory assets were not earning a rate of return.

If, for any reason, the Company's regulated businesses cease to meet the criteria for application of regulatory accounting for all or part of their operations, the regulatory assets and liabilities relating to those portions ceasing to meet such criteria would be removed from the balance sheet and included in the statement of income or accumulated other comprehensive income (loss) in the period in which the discontinuance of regulatory accounting occurs.