Consolidated Balance Sheets (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2013
Dec. 31, 2012
Property plant and equipment    
Utility plant—at original cost, net of accumulated depreciation of $3,894,326 in 2013 and $3,657,221 in 2012 $ 12,244,359 $ 11,584,944
Nonutility property, net of accumulated depreciation of $228,465 in 2013 and $199,467 in 2012 146,803 154,420
Total property, plant and equipment 12,391,162 11,739,364
Current assets    
Cash and cash equivalents 26,964 24,433
Restricted funds 28,505 29,756
Accounts receivable 244,568 221,655
Allowance for uncollectible accounts (33,953) (26,874)
Unbilled revenues 217,147 180,628
Income taxes receivable 5,778 9,594
Materials and supplies 32,973 29,772
Other 28,408 30,483
Total current assets 550,390 499,447
Regulatory and other long-term assets    
Regulatory assets 858,465 1,199,114
Restricted funds 754 10,791
Goodwill 1,207,764 1,207,250
Other 60,998 63,010
Total regulatory and other long-term assets 2,127,981 2,480,165
TOTAL ASSETS 15,069,533 14,718,976
Capitalization    
Common stock ($0.01 par value, 500,000 shares authorized, 178,379 shares outstanding in 2013 and 176,988 in 2012) 1,784 1,770
Paid-in-capital 6,261,396 6,222,644
Accumulated deficit (1,495,698) (1,664,955)
Accumulated other comprehensive income (34,635) (116,191)
Treasury stock (5,043) 0
Common stockholders' equity 4,727,804 4,443,268
Preferred stock without mandatory redemption requirements 0 1,720
Total stockholders' equity 4,727,804 4,444,988
Long-term debt    
Long-term debt 5,212,881 5,190,509
Redeemable preferred stock at redemption value 17,177 18,861
Total capitalization 9,957,862 9,654,358
Current liabilities    
Short-term debt 630,307 269,985
Current portion of long-term debt 14,174 115,919
Accounts payable 264,589 279,613
Taxes accrued 32,400 35,555
Interest accrued 52,087 53,810
Other 241,976 239,950
Total current liabilities 1,235,533 994,832
Regulatory and other long-term liabilities    
Advances for construction 375,729 379,737
Deferred income taxes 1,822,088 1,545,513
Deferred investment tax credits 26,408 27,909
Regulatory liabilities 373,319 364,181
Accrued pension expense 108,542 461,647
Accrued postretirement benefit expense 88,419 254,147
Other 38,929 40,516
Total regulatory and other long-term liabilities 2,833,434 3,073,650
Contributions in aid of construction 1,042,704 996,136
Commitments and contingencies (See Note 15)      
TOTAL CAPITALIZATION AND LIABILITIES $ 15,069,533 $ 14,718,976