CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Operating activities
Net income	$ 93,285	$ 96,630
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	84,948	81,284
Demand side management program amortization	1,392	2,546
Deferred income taxes	49,182	47,172
Amortization of investment tax credits	(651)	(668)
Allowance for equity funds used during construction	(2,726)	(1,619)
Net derivative losses	6,496	18,520
Changes in operating assets and liabilities:
Accounts receivable	30,996	11,885
Accrued unbilled revenues	112,150	76,879
Inventories	56,836	37,815
Prepayments and other	(3,250)	28,913
Accounts payable	(124,292)	(55,823)
Net regulatory assets and liabilities	10,147	2,239
Other current liabilities	39,057	43,374
Pension and other employee benefit obligations	(39,547)	(57,910)
Change in other noncurrent assets	(6,434)	(283)
Change in other noncurrent liabilities	(1,297)	(5,588)
Net cash provided by operating activities	306,292	325,366
Investing activities
Utility capital/construction expenditures	(152,420)	(115,991)
Allowance for equity funds used during construction	2,726	1,619
Investments in utility money pool	(383,000)	0
Repayments from utility money pool	363,000	0
Net cash used in investing activities	(169,694)	(114,372)
Financing activities
Repayments of short-term borrowings, net	0	(227,400)
Borrowings under utility money pool arrangement	0	120,000
Repayments under utility money pool arrangement	0	(120,000)
Capital contributions from parent	0	75,000
Dividends paid to parent	(134,004)	(66,828)
Net cash used in financing activities	(134,004)	(219,228)
Net change in cash and cash equivalents	2,594	(8,234)
Cash and cash equivalents at beginning of period	3,763	32,912
Cash and cash equivalents at end of period	6,357	24,678
Supplemental disclosure of cash flow information:
Cash paid for interest (net of amounts capitalized)	(44,384)	(39,145)
Cash received for income taxes, net	3,623	33,696
Supplemental disclosure of non-cash investing transactions:
Property, plant and equipment additions in accounts payable	$ 60,020	$ 91,478