CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Operating activities
Net income	$ 118,403	$ 116,605
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	94,654	90,809
Demand side management program amortization	1,144	1,257
Deferred income taxes	41,863	66,372
Amortization of investment tax credits	(734)	(740)
Allowance for equity funds used during construction	(11,430)	(5,923)
Net realized and unrealized hedging and derivative transactions	2,818	(164)
Changes in operating assets and liabilities:
Accounts receivable	410	41,048
Accrued unbilled revenues	63,760	49,579
Inventories	56,296	42,434
Prepayments and other	7,395	(10,662)
Accounts payable	(29,270)	(18,383)
Net regulatory assets and liabilities	10,199	67,907
Other current liabilities	38,157	10,870
Pension and other employee benefit obligations	(35,614)	(44,273)
Change in other noncurrent assets	4,616	3,779
Change in other noncurrent liabilities	(891)	1,720
Net cash provided by operating activities	361,776	412,235
Investing activities
Utility capital/construction expenditures	(299,086)	(226,948)
Allowance for equity funds used during construction	11,430	5,923
Investments in utility money pool arrangement	(495,000)	(276,000)
Repayments from utility money pool arrangement	317,000	76,000
Net cash used in investing activities	(465,656)	(421,025)
Financing activities
Repayments of short-term borrowings, net	0	(154,000)
Borrowings under utility money pool arrangement	2,000	14,000
Repayments under utility money pool arrangement	(2,000)	(14,000)
Proceeds from issuance of long-term debt	296,045	493,164
Repayments of long-term debt	0	(250,000)
Dividends paid to parent	(195,134)	(66,803)
Net cash provided by financing activities	100,911	22,361
Net change in cash and cash equivalents	(2,969)	13,571
Cash and cash equivalents at beginning of period	21,089	5,150
Cash and cash equivalents at end of period	18,120	18,721
Supplemental disclosure of cash flow information:
Cash paid for interest (net of amounts capitalized)	(55,003)	(54,770)
Cash received (paid) for income taxes, net	4,902	(16,308)
Supplemental disclosure of non-cash investing transactions:
Property, plant and equipment additions in accounts payable	$ 93,872	$ 81,470