Regulatory Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2011

Regulatory Assets and Liabilities Disclosure [Abstract]

Regulatory Assets and Liabilities

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

	Estimated Recovery Period	*	2011		2010
			(In thousands)
Regulatory assets:
Pension and postretirement benefits (a)	(e)		171,492		103,818
Deferred income taxes	**		119,189		114,427
Taxes recoverable from customers (a)	—		12,433		11,961
Plant costs (a)	Over plant lives		10,256		9,964
Long-term debt refinancing costs (a)	Up to 27 years		10,112		11,101
Costs related to identifying generation development (a)	Up to 15 years		9,817		13,777
Natural gas supply derivatives (b)	Up to 1 year		437		9,359
Natural gas cost recoverable through rate adjustments (b)	Up to 28 months		2,622		6,609
Other (a) (b)	Largely within 1 year		22,651		35,225
Total regulatory assets			359,009		316,241
Regulatory liabilities:
Plant removal and decommissioning costs (c)			289,972		276,652
Deferred income taxes**			84,963		64,017
Natural gas costs refundable through rate adjustments (d)			45,064		36,996
Taxes refundable to customers (c)			31,837		19,352
Other (c) (d)			8,393		16,080
Total regulatory liabilities			460,229		413,097
Net regulatory position			(101,220	)	(96,856	)

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

** Represents deferred income taxes related to regulatory assets and liabilities. The deferred income tax assets are not earning a rate of return.

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

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

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

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

(e) Recovered as expense is incurred.