Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Operating activities:
Net income	$ 3,940	$ 42,893
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	69,975	68,521
Debt amortization	1,086	1,198
Deferred income taxes	(19,786)	5,796
Net changes in:
Current assets and liabilities	2,840	(78,026)
Regulatory assets	73,055	25,851
Long-term power contract obligations	(7,750)	(21,585)
Deferred debits and credits, net	(19,570)	3,256
Net cash provided by operating activities	103,790	47,904
Investing activities:
Plant expenditures (including AFUDC)	(98,668)	(72,811)
Decrease in restricted cash		17,007
Net change in other investment activities	375
Net cash used in investing activities	(98,293)	(55,804)
Financing activities:
Transition property securitization redemptions	(18,725)	(21,336)
Long-term debt redemptions	(412)	(412)
Net change in notes payable	71,000	79,000
Dividends paid	(57,590)	(50,490)
Net cash (used in) provided by financing activities	(5,727)	6,762
Net decrease in cash and cash equivalents	(230)	(1,138)
Cash and cash equivalents at the beginning of the year	9,373	8,964
Cash and cash equivalents at the end of the period	9,143	7,826
Cash paid during the period for:
Interest, net of amounts capitalized	16,107	17,605
Income taxes	7,176	13,100
Non-cash investing activity:
Plant additions included in accounts payable	$ 29,470	$ 13,498