CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Operating activities:
Net income (loss)	$ 107,592	$ 167,475
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	91,184	88,178
Amortization	10,535	5,744
Conservation amortization	28,982	34,107
Deferred income taxes and tax credits, net	41,520	70,591
Net unrealized (gain) loss on derivative instruments	(8,793)	(75,937)
Derivative contracts classified as financing activities due to merger	8,026	26,049
AFUDC - Equity	(1,436)	(6,524)
Funding of pension liability	(3,000)	(5,100)
Regulatory Assets	(38,240)	(28,953)
Regulatory liabilities	6,407	3,029
Other long-term assets	(5,667)	3,099
Other long-term liabilities	21,532	17,586
Change in certain current assets and liabilities:
Accounts receivable and unbilled revenue	28,650	31,548
Materials and supplies	214	1,827
Fuel and gas inventory	35,451	27,097
Income taxes	148	148
Prepayments and other	539	(3,732)
Purchased gas adjustment	(3,079)	(5,718)
Accounts payable	(13,886)	(47,935)
Taxes payable	11,476	16,746
Accrued expenses and other	(7,621)	(18,060)
Net cash provided by operating activities	310,534	301,265
Investing activities:
Construction expenditures - excluding equity AFUDC	(96,318)	(168,337)
Proceeds from disposition of assets	0	108,166
Restricted cash	(18,266)	599
Other	(4,125)	(4,248)
Net cash used in investing activities	(118,709)	(63,820)
Financing activities:
Change in short-term debt and leases, net	(163,903)	(157,895)
Dividends paid	(42,081)	(42,071)
Redemption of bonds and notes	0	(29,000)
Derivative contracts classified as financing activities due to merger	(8,026)	(26,049)
Issuance cost of bonds and other	1,464	(3,984)
Net cash provided by (used in) financing activities	(212,546)	(258,999)
Net increase (decrease) in cash and cash equivalents	(20,721)	(21,554)
Cash and cash equivalents at beginning of period	44,302	135,542
Cash and cash equivalents at end of period	23,581	113,988
Supplemental cash flow information:
Cash payments for interest (net of capitalized interest)	90,756	78,346
Subsidiaries [Member]
Operating activities:
Net income (loss)	121,083	179,938
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	91,184	88,178
Amortization	10,535	5,744
Conservation amortization	28,982	34,107
Deferred income taxes and tax credits, net	51,543	79,761
Net unrealized (gain) loss on derivative instruments	(7,270)	(72,740)
AFUDC - Equity	(1,436)	(6,524)
Funding of pension liability	(3,000)	(5,100)
Regulatory Assets	(38,240)	(28,953)
Regulatory liabilities	6,407	3,029
Other long-term assets	(3,251)	2,922
Other long-term liabilities	19,275	18,162
Change in certain current assets and liabilities:
Accounts receivable and unbilled revenue	28,691	31,313
Materials and supplies	214	1,827
Fuel and gas inventory	35,451	27,097
Income taxes	148	148
Prepayments and other	539	(3,732)
Purchased gas adjustment	(3,079)	(5,718)
Accounts payable	(13,886)	(47,721)
Taxes payable	11,476	16,746
Accrued expenses and other	(1,276)	(8,783)
Net cash provided by operating activities	334,090	309,701
Investing activities:
Construction expenditures - excluding equity AFUDC	(96,318)	(168,337)
Proceeds from disposition of assets	0	108,166
Restricted cash	(18,266)	599
Other	(3,507)	(4,184)
Net cash used in investing activities	(118,091)	(63,756)
Financing activities:
Change in short-term debt and leases, net	(163,903)	(157,895)
Dividends paid	(74,114)	(105,648)
Issuance cost of bonds and other	1,463	(3,985)
Net cash provided by (used in) financing activities	(236,554)	(267,528)
Net increase (decrease) in cash and cash equivalents	(20,555)	(21,583)
Cash and cash equivalents at beginning of period	44,111	135,530
Cash and cash equivalents at end of period	23,556	113,947
Supplemental cash flow information:
Cash payments for interest (net of capitalized interest)	$ 59,666	$ 57,646