CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Operating activities:
Net income (loss)	$ 148,705	$ 168,380
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	183,646	178,480
Amortization	23,270	12,177
Conservation amortization	51,508	56,576
Deferred income taxes and tax credits, net	56,679	69,635
Net unrealized (gain) loss on derivative instruments	(25,664)	(53,496)
Derivative contracts classified as financing activities due to merger	8,026	26,013
AFUDC - Equity	(3,405)	(11,222)
Funding of pension liability	(6,000)	(10,200)
Regulatory Assets	(80,365)	(66,102)
Regulatory liabilities	3,668	10,341
Other long-term assets	(6,477)	10,842
Other long-term liabilities	37,739	54,837
Change in certain current assets and liabilities:
Accounts receivable and unbilled revenue	228,718	136,457
Materials and supplies	5,482	(2,184)
Fuel and gas inventory	2,359	11,104
Income taxes	297	4,795
Prepayments and other	(1,273)	(7,340)
Purchased gas adjustment	(18,477)	(18,078)
Accounts payable	(64,794)	(74,666)
Taxes payable	(17,536)	(11,589)
Accrued expenses and other	(8,884)	(15,507)
Net cash provided by operating activities	517,222	469,253
Investing activities:
Construction expenditures - excluding equity AFUDC	(217,381)	(326,082)
Treasury grant payment received	107,794	0
Proceeds from disposition of assets	0	108,166
Restricted cash	(47,793)	(1,023)
Other	(11,058)	(5,119)
Net cash used in investing activities	(168,438)	(224,058)
Financing activities:
Change in short-term debt and leases, net	(165,789)	(184,789)
Dividends paid	(137,779)	(84,609)
Long-term notes and bonds issued	299,000	161,860
Redemption of bonds and notes	(299,000)	(216,860)
Derivative contracts classified as financing activities due to merger	(8,026)	(26,013)
Issuance cost of bonds and other	3,215	(2,722)
Net cash provided by (used in) financing activities	(308,379)	(353,133)
Net increase (decrease) in cash and cash equivalents	40,405	(107,938)
Cash and cash equivalents at beginning of period	44,302	135,542
Cash and cash equivalents at end of period	84,707	27,604
Supplemental cash flow information:
Cash payments for interest (net of capitalized interest)	172,106	162,588
Cash payments (refunds) for income taxes	0	(4,500)
Subsidiaries [Member]
Operating activities:
Net income (loss)	178,916	206,601
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	183,646	178,480
Amortization	23,270	12,177
Conservation amortization	51,508	56,576
Deferred income taxes and tax credits, net	74,883	90,940
Net unrealized (gain) loss on derivative instruments	(24,364)	(45,365)
AFUDC - Equity	(3,405)	(11,222)
Funding of pension liability	(6,000)	(10,200)
Regulatory Assets	(80,365)	(66,102)
Regulatory liabilities	3,668	10,341
Other long-term assets	(1,650)	14,921
Other long-term liabilities	33,339	33,285
Change in certain current assets and liabilities:
Accounts receivable and unbilled revenue	228,559	130,617
Materials and supplies	5,482	(2,184)
Fuel and gas inventory	2,359	11,104
Income taxes	297	4,795
Prepayments and other	(1,273)	(7,340)
Purchased gas adjustment	(18,477)	(18,078)
Accounts payable	(64,794)	(68,819)
Taxes payable	(17,536)	(11,589)
Accrued expenses and other	(9,620)	(17,586)
Net cash provided by operating activities	558,443	491,352
Investing activities:
Construction expenditures - excluding equity AFUDC	(217,381)	(326,082)
Treasury grant payment received	107,794	0
Proceeds from disposition of assets	0	108,166
Restricted cash	(47,793)	(1,023)
Other	(9,818)	(4,902)
Net cash used in investing activities	(167,198)	(223,841)
Financing activities:
Change in short-term debt and leases, net	(165,789)	(184,789)
Dividends paid	(203,628)	(188,064)
Loan from (payment to) parent	(665)	0
Long-term notes and bonds issued	0	161,860
Redemption of bonds and notes	0	(161,860)
Issuance cost of bonds and other	3,886	(2,725)
Net cash provided by (used in) financing activities	(366,196)	(375,578)
Net increase (decrease) in cash and cash equivalents	25,049	(108,067)
Cash and cash equivalents at beginning of period	44,111	135,530
Cash and cash equivalents at end of period	69,160	27,463
Supplemental cash flow information:
Cash payments for interest (net of capitalized interest)	123,345	122,892
Cash payments (refunds) for income taxes	$ 0	$ (4,500)