CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income	$ 439,966	$ 413,164	$ 366,940
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on sale of energy-related products and services business			(10,404)
Depreciation and amortization including nuclear fuel	492,322	481,262	493,784
Deferred fuel and purchased power	21,678	71,573	69,166
Deferred fuel and purchased power amortization	31,190	(116,716)	(155,157)
Allowance for equity funds used during construction	(25,581)	(22,436)	(23,707)
Deferred income taxes	249,296	187,023	117,952
Deferred investment tax credit	52,542	41,579	58,240
Change in derivative instruments fair value	534	(749)	4,064
Changes in current assets and liabilities:
Customer and other receivables	(44,991)	14,587	40,626
Accrued unbilled revenues	(1,951)	30,394	(21,947)
Materials, supplies and fossil fuel	(11,878)	(23,043)	(23,398)
Income tax receivable	(133,094)	(4,043)	3,983
Other current assets	(17,913)	(27,352)	(3,079)
Accounts payable	45,414	(96,600)	58,346
Accrued taxes	6,059	12,736	8,085
Other current liabilities	(7,513)	23,869	20,358
Change in margin and collateral accounts - assets	993	2,216	33,349
Change in margin and collateral accounts - liabilities	12,355	137,785	29,731
Change in long term income tax receivable	137,270	(1,756)	(3,530)
Change in unrecognized tax benefits	(91,425)	(2,583)	8,410
Change in other regulatory liabilities	64,473	13,539	37,009
Change in other long-term assets	(41,757)	6,872	(41,722)
Change in other long-term liabilities	(24,682)	29,801	58,484
Net cash flow provided by operating activities	1,153,307	1,171,122	1,125,583
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,016,322)	(889,551)	(884,350)
Contributions in aid of construction	41,090	49,876	38,096
Allowance for borrowed funds used during construction	(14,861)	(14,971)	(18,358)
Proceeds from sale of energy-related products and services business	0		45,111
Proceeds from nuclear decommissioning trust sales	446,025	417,603	497,780
Investment in nuclear decommissioning trust	(463,274)	(434,852)	(513,799)
Proceeds from sale of life insurance policies			55,444
Other	(2,059)	(1,099)	(1,931)
Net cash flow used for investing activities	(1,009,401)	(872,994)	(782,007)
CASH FLOWS FROM FINANCING ACTIVITIES
Issuance of long-term debt	136,307	476,081	470,353
Repayment of long-term debt	(122,828)	(654,286)	(655,169)
Short-term borrowings and payments - net	60,950	92,175	(16,600)
Dividends paid on common stock	(235,244)	(225,075)	(221,728)
Common stock equity issuance	17,319	15,955	15,841
Distributions to noncontrolling interests	(17,385)	(10,529)	(10,210)
Other	299	170	(2,668)
Net cash flow used for financing activities	(160,582)	(305,509)	(420,181)
NET DECREASE IN CASH AND CASH EQUIVALENTS	(16,676)	(7,381)	(76,605)
CASH AND CASH EQUIVALENTS AT BEGINNING OF YEAR	26,202	33,583	110,188
CASH AND CASH EQUIVALENTS AT END OF YEAR	$ 9,526	$ 26,202	$ 33,583