CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 346,950	$ 357,708
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on sale of district cooling business		(41,973)
Gain on sale of energy-related products and services business	(10,404)
Depreciation and amortization including nuclear fuel	370,107	350,762
Deferred fuel and purchased power	30,965	50,020
Deferred fuel and purchased power amortization	(121,018)	(95,926)
Allowance for equity funds used during construction	(18,697)	(16,417)
Real estate impairment charges		16,731
Gain on real estate debt restructuring		(14,403)
Deferred income taxes	131,582	281,486
Change in mark-to-market valuations	1,861	3,716
Changes in current assets and liabilities:
Customer and other receivables	(47,410)	(103,973)
Accrued unbilled revenues	(80,877)	(69,035)
Materials, supplies and fossil fuel	(25,532)	19,011
Other current assets	(1,581)	(6,027)
Accounts payable	29,340	36,687
Accrued taxes and income tax receivable-net	89,534	56,851
Other current liabilities	30,300	6,738
Change in margin and collateral accounts - assets	33,591	(4,336)
Change in margin and collateral accounts - liabilities	85,785	(143,725)
Change in unrecognized tax benefits	12,123	(72,649)
Change in other long-term assets	(10,678)	(59,382)
Change in other long-term liabilities	74,565	17,636
Net cash flow provided by operating activities	920,506	569,500
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(643,261)	(552,707)
Contributions in aid of construction	36,351	25,258
Allowance for borrowed funds used during construction	(14,371)	(12,553)
Proceeds from sale of district cooling business		100,300
Proceeds from sale of energy-related products and services business	45,111
Proceeds from nuclear decommissioning trust sales	405,637	424,255
Investment in nuclear decommissioning trust	(417,957)	(442,567)
Proceeds from sale of commercial real estate investments	1,100	71,174
Proceeds from sale of life insurance policies	55,444
Other	(2,346)	9,621
Net cash flow used for investing activities	(534,292)	(377,219)
CASH FLOWS FROM FINANCING ACTIVITIES
Issuance of long-term debt	470,353
Repayment of long-term debt	(228,457)	(84,529)
Short-term borrowings and payments - net	(16,600)	(153,715)
Dividends paid on common stock	(166,197)	(161,722)
Common stock equity issuance	14,953	255,156
Distributions to noncontrolling interests	(2,610)	(3,286)
Other	(3,132)	6,352
Net cash flow provided by (used for) financing activities	68,310	(141,744)
NET INCREASE IN CASH AND CASH EQUIVALENTS	454,524	50,537
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	110,188	145,378
CASH AND CASH EQUIVALENTS AT END OF PERIOD	564,712	195,915
Cash paid during the period for:
Income taxes, net of (refunds)	5,676	(22,165)
Interest, net of amounts capitalized	$ 163,250	$ 167,576