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	$ 78,062	$ 56,547
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Depreciation of property, plant and equipment	75,517	75,243
Other amortization	2,999	11,965
Provision for loan losses	5,924	7,105
Loans receivable originated and purchased, held for sale	(161,344)	(64,028)
Proceeds from sale of loans receivable, held for sale	161,713	71,829
Change in deferred income taxes	41,541	39,051
Change in excess tax benefits from share-based payment arrangements	(40)	(55)
Allowance for equity funds used during construction	(3,937)	(2,561)
Change in cash overdraft		(2,305)
Changes in assets and liabilities
Increase in accounts receivable and unbilled revenues, net	(42,428)	(52,537)
Increase in fuel oil stock	(35,893)	(6,509)
Decrease (increase) in accounts, interest and dividends payable	3,578	(41,989)
Change in prepaid and accrued income taxes and utility revenue taxes	(12,998)	8,333
Contributions to defined benefit pension and other postretirement benefit plans	(53,356)	(37,556)
Change in other assets and liabilities	(62,910)	(7,352)
Net cash provided by (used in) operating activities	(3,572)	55,181
Cash flows from investing activities
Available-for-sale investment and mortgage-related securities purchased	(93,808)	(193,119)
Principal repayments on available-for-sale investment and mortgage-related securities	75,407	161,526
Proceeds from sale of available-for-sale investment and mortgage-related securities	3,548	2,066
Net increase in loans held for investment	(61,214)	(104,824)
Proceeds from sale of real estate acquired in settlement of loans	6,036	3,977
Capital expenditures	(145,263)	(89,088)
Contributions in aid of construction	26,981	8,153
Other		(2,911)
Net cash used in investing activities	(188,313)	(214,220)
Cash flows from financing activities
Net increase in deposit liabilities	66,709	79,577
Net increase (decrease) in short-term borrowings with original maturities of three months or less	27,419	(24,923)
Net increase (decrease) in retail repurchase agreements	(14,556)	1,803
Proceeds from issuance of long-term debt	417,000	125,000
Repayment of long-term debt	(328,500)	(50,000)
Change in excess tax benefits from share-based payment arrangements	40	55
Net proceeds from issuance of common stock	11,909	12,071
Common stock dividends	(47,851)	(47,331)
Preferred stock dividends of subsidiaries	(946)	(946)
Other	(2,055)	(172)
Net cash provided by financing activities	129,169	95,134
Net decrease in cash and cash equivalents	(62,716)	(63,905)
Cash and cash equivalents, beginning of period	270,265	330,651
Cash and cash equivalents, end of period	$ 207,549	$ 266,746