CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Operating activities
Net income	$ 433,427	$ 366,953
Remove loss (income) from discontinued operations	43	(109)
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	507,658	464,117
Conservation and demand side management program amortization	3,425	3,765
Nuclear fuel amortization	49,485	49,765
Deferred income taxes	235,684	278,358
Amortization of investment tax credits	(3,314)	(3,104)
Allowance for equity funds used during construction	(41,863)	(28,644)
Equity earnings of unconsolidated subsidiaries	(15,106)	(14,660)
Dividends from unconsolidated subsidiaries	18,683	8,028
Share-based compensation expense	18,747	17,249
Net realized and unrealized hedging and derivative transactions	(2,754)	7,325
Changes in operating assets and liabilities:
Accounts receivable	(78,940)	(928)
Accrued unbilled revenues	37,069	139,012
Inventories	40,684	145,095
Other current assets	29,700	(61,291)
Accounts payable	1,625	(177,076)
Net regulatory assets and liabilities	76,693	12,912
Other current liabilities	(83,336)	(117,653)
Pension and other employee benefit obligations	(170,162)	(168,898)
Change in other noncurrent assets	16,940	(40,893)
Change in other noncurrent liabilities	(163)	(14,027)
Net cash provided by operating activities	1,074,225	865,296
Investing activities
Utility capital/construction expenditures	(1,596,778)	(1,103,562)
Proceeds from insurance recoveries	50,000	24,000
Allowance for equity funds used during construction	41,863	28,644
Purchases of investments in external decommissioning fund	(890,700)	(371,361)
Proceeds from the sale of investments in external decommissioning fund	887,500	371,361
Investment in WYCO Development LLC	(2,166)	(379)
Change in restricted cash	0	94,959
Other, net	(1,696)	(24)
Net cash used in investing activities	(1,511,977)	(956,362)
Financing activities
(Repayments of) proceeds from short-term borrowings, net	(248,000)	262,000
Proceeds from issuance of long-term debt	1,337,045	111,015
Repayments of long-term debt, including reacquisition premiums	(651,516)	(2,455)
Proceeds from issuance of common stock	227,113	3,698
Repurchase of common stock	0	(18,529)
Purchase of common stock for settlement of equity awards	0	(23,307)
Dividends paid	(250,392)	(238,510)
Net cash provided by financing activities	414,250	93,912
Net change in cash and cash equivalents	(23,502)	2,846
Cash and cash equivalents at beginning of period	82,323	60,684
Cash and cash equivalents at end of period	58,821	63,530
Supplemental disclosure of cash flow information:
Cash paid for interest (net of amounts capitalized)	(258,124)	(281,266)
Cash received (paid) for income taxes, net	13,681	(5,875)
Supplemental disclosure of non-cash investing and financing transactions:
Property, plant and equipment additions in accounts payable	302,434	274,350
Issuance of common stock for reinvested dividends and 401(k) plans	$ 37,504	$ 35,543