CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Operating activities
Net income	$ 308,366	$ 320,026
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	249,396	212,353
Demand side management program amortization	6,484	17,120
Deferred income taxes	183,918	94,588
Amortization of investment tax credits	(2,002)	(1,752)
Allowance for equity funds used during construction	(5,373)	(8,801)
Net realized and unrealized hedging and derivative transactions	16,789	(47,982)
Changes in operating assets and liabilities:
Accounts receivable	12,232	73,274
Accrued unbilled revenues	77,382	109,790
Inventories	(38,563)	(4,783)
Prepayments and other	28,297	43,106
Accounts payable	(38,903)	(154,001)
Net regulatory assets and liabilities	14,038	44,351
Other current liabilities	2,508	10,068
Pension and other employee benefit obligations	(60,047)	(15,550)
Change in other noncurrent assets	3,467	(2,676)
Change in other noncurrent liabilities	(13,108)	(11,811)
Net cash provided by operating activities	744,881	677,320
Investing activities
Utility capital/construction expenditures	(475,444)	(382,902)
Allowance for equity funds used during construction	5,373	8,801
Investments in utility money pool	(268,300)	(697,500)
Repayments from utility money pool	199,300	636,500
Net cash used in investing activities	(539,071)	(435,101)
Financing activities
Repayment of short-term borrowings, net	(269,400)	(95,000)
Borrowings under utility money pool arrangement	203,800	184,900
Repayments under utility money pool arrangement	(203,800)	(268,900)
Proceeds from issuance of long-term debt	246,602	0
Capital contributions from parent	76,221	137,791
Dividends paid to parent	(202,636)	(199,206)
Net cash used in financing activities	(149,213)	(240,415)
Net increase in cash and cash equivalents	56,597	1,804
Cash and cash equivalents at beginning of period	32,912	33,429
Cash and cash equivalents at end of period	89,509	35,233
Supplemental disclosure of cash flow information:
Cash paid for interest (net of amounts capitalized)	(125,727)	(117,053)
Cash received (paid) for income taxes, net	30,575	(46,150)
Supplemental disclosure of non-cash investing transactions:
Property, plant and equipment additions in accounts payable	$ 102,078	$ 16,752