CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 166,075	$ 172,434
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization including nuclear fuel	246,371	249,482
Deferred fuel and purchased power	1,315	36,183
Deferred fuel and purchased power amortization	18,399	10,921
Allowance for equity funds used during construction	(14,941)	(13,129)
Deferred income taxes	32,611	68,526
Deferred investment tax credit	28,875	20,159
Change in derivative instruments fair value	49	349
Changes in current assets and liabilities:
Customer and other receivables	(64,986)	(79,408)
Accrued unbilled revenues	(75,648)	(68,763)
Materials, supplies and fossil fuel	(9,435)	(4,002)
Income tax receivable	135,517	779
Other current assets	(14,038)	(14,439)
Accounts payable	30,725	85,563
Accrued taxes	30,709	4,253
Other current liabilities	19,978	(26,098)
Change in margin and collateral accounts - assets	(2,107)	(1,111)
Change in margin and collateral accounts - liabilities	(22,425)	14,600
Change in other long-term assets	(19,243)	(23,796)
Change in other long-term liabilities	(22,735)	21,753
Net cash flow provided by operating activities	465,066	454,256
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(388,752)	(376,601)
Contributions in aid of construction	12,646	21,236
Allowance for borrowed funds used during construction	(7,560)	(7,626)
Proceeds from nuclear decommissioning trust sales	199,224	253,996
Investment in nuclear decommissioning trust	(207,848)	(262,621)
Other	(678)	(262)
Net cash flow used for investing activities	(392,968)	(371,878)
CASH FLOWS FROM FINANCING ACTIVITIES
Issuance of long-term debt	535,975	136,307
Repayment of long-term debt	(503,583)	(40,127)
Short-term borrowings and payments - net	23,525	(62,075)
Dividends paid on common stock	(125,138)	(116,231)
Common stock equity issuance	12,625	9,751
Distributions to noncontrolling interests	(15,869)	(9,197)
Other	2	795
Net cash flow used for financing activities	(72,463)	(80,777)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(365)	1,601
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	9,526	26,202
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 9,161	$ 27,803