Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 148,780	$ 107,343
Adjustments
Depreciation and amortization	184,433	174,220
Provision for deferred income taxes	57,833	69,579
Amortization of deferred investment tax credits	(759)	(771)
Provision for losses on utility accounts receivable	7,402	7,774
Allowance for other funds used during construction	(9,438)	(5,363)
(Gain) loss on asset dispositions and purchases	(626)	296
Pension and non-pension post retirement benefits	40,283	35,720
Other, net	(18,922)	25,475
Changes in assets and liabilities
Receivables and unbilled utility revenues	(75,541)	(44,705)
Income taxes receivable	1,850	(3,443)
Other current assets	665	(35,564)
Pension and non-pension post retirement benefit contributions	(62,591)	(72,006)
Accounts payable	(43,252)	(14,728)
Taxes accrued, including income taxes	68,804	15,580
Interest accrued	(2,051)	(1,306)
Change in book overdraft	21,515	0
Other current liabilities	(1,514)	4,295
Net cash provided by operating activities	316,871	262,396
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(476,300)	(391,792)
Acquisitions	(44,293)	(4,769)
Proceeds from sale of assets and securities	560,010	6,657
Removal costs from property, plant and equipment retirements, net	(24,634)	(24,038)
Net restricted funds released	14,886	38,517
Net cash provided by (used in) investing activities	29,669	(375,425)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from long-term debt	14,730	12,275
Repayment of long-term debt	(158,188)	(64,208)
Net (repayments) borrowings under short-term debt agreements	(119,077)	247,946
Proceeds from issuances of employee stock plans and DRIP	12,594	8,852
Advances and contributions for construction, net of refunds of $6,491 and $8,550 at June 30, 2012 and 2011, respectively	16,720	11,193
Change in bank overdraft position	(34,812)	(25,411)
Debt issuance costs	0	(552)
Redemption of preferred stock	(1,100)	(6)
Dividends paid	(80,943)	(77,105)
Other	2,248	399
Net cash (used in) provided by financing activities	(347,828)	113,383
Net (decrease) increase in cash and cash equivalents	(1,288)	354
Cash and cash equivalents at beginning of period	14,207	13,112
Cash and cash equivalents at end of period	12,919	13,466
Non-cash investing activity:
Capital expenditures acquired on account but unpaid at quarter-end	93,783	80,573
Non-cash financing activity:
Long-term debt	68,746	0
Dividends accrued	44,079	40,351
Advances and contributions	$ 6,188	$ 10,027