Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities
Net income	$ 126,239	$ 105,422
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation of property, plant and equipment	112,946	111,516
Other amortization	4,811	14,552
Provision for loan losses	9,504	10,927
Loans receivable originated and purchased, held for sale	(304,289)	(137,507)
Proceeds from sale of loans receivable, held for sale	302,844	127,163
Change in deferred income taxes	82,582	60,957
Change in excess tax benefits from share-based payment arrangements	(65)	(39)
Allowance for equity funds used during construction	(5,548)	(4,131)
Change in cash overdraft		(2,688)
Changes in assets and liabilities
Increase in accounts receivable and unbilled revenues, net	(30,610)	(75,905)
Increase in fuel oil stock	(31,372)	(4,592)
Decrease in accounts, interest and dividends payable	(5,905)	(57,746)
Change in prepaid and accrued income taxes and utility revenue taxes	(5,121)	40,418
Contributions to defined benefit pension and other postretirement benefit plans	(64,006)	(56,395)
Change in other assets and liabilities	(70,406)	(30,863)
Net cash provided by operating activities	121,604	101,089
Cash flows from investing activities
Available-for-sale investment and mortgage-related securities purchased	(146,794)	(202,061)
Principal repayments on available-for-sale investment and mortgage-related securities	104,310	283,931
Proceeds from sale of available-for-sale investment and mortgage-related securities	3,548	32,799
Net increase in loans held for investment	(75,982)	(153,745)
Proceeds from sale of real estate acquired in settlement of loans	9,659	5,298
Capital expenditures	(225,961)	(148,107)
Contributions in aid of construction	33,106	15,106
Other	865	(2,923)
Net cash used in investing activities	(297,249)	(169,702)
Cash flows from financing activities
Net increase in deposit liabilities	56,756	87,429
Net increase in short-term borrowings with original maturities of three months or less	13,398	26,272
Net increase (decrease) in retail repurchase agreements	(22,011)	614
Proceeds from issuance of long-term debt	457,000	125,000
Repayment of long-term debt	(368,500)	(150,000)
Change in excess tax benefits from share-based payment arrangements	65	39
Net proceeds from issuance of common stock	16,881	14,861
Common stock dividends	(71,966)	(77,070)
Preferred stock dividends of subsidiaries	(1,417)	(1,417)
Other	(6,314)	(4,283)
Net cash provided by (used in) financing activities	73,892	21,445
Net increase (decrease) in cash and cash equivalents	(101,753)	(47,168)
Cash and cash equivalents, beginning of period	270,265	330,651
Cash and cash equivalents, end of period	$ 168,512	$ 283,483