Consolidated Statements of Operations and Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Operating revenues	$ 2,901,858		$ 2,876,889		$ 2,666,236
Operating expenses
Operation and maintenance	1,312,724		1,350,040		1,301,794
Depreciation and amortization	407,718		381,503		351,821
General taxes	234,642		221,212		210,478
(Gain) loss on asset dispositions and purchases	925		(839)		(993)
Total operating expenses, net	1,956,009		1,951,916		1,863,100
Operating income	945,849		924,973		803,136
Other income (expenses)
Interest, net	(308,164)		(310,794)		(312,415)
Loss on extinguishment of debt	(40,583)		0		0
Allowance for other funds used during construction	12,639		15,592		13,131
Allowance for borrowed funds used during construction	6,377		7,771		5,923
Amortization of debt expense	(6,603)		(5,358)		(5,055)
Other, net	(4,045)		(926)		(1,040)
Total other income (expenses)	(340,379)		(293,715)		(299,456)
Income from continuing operations before income taxes	605,470		631,258		503,680
Provision for income taxes	236,206		257,008		198,751
Income from continuing operations	369,264		374,250		304,929
Income (loss) from discontinued operations	0		(16,180)		4,684
Net income	369,264		358,070		309,613
Other comprehensive income (loss), net of tax:
Change in employee benefit plan funded status, net of tax of $46,974, $(16,894) and $(19,498), respectively	73,472		(26,425)		(30,497)
Pension plan amortized to periodic benefit cost:
Prior service cost, net of tax of $111, $113 and $112, respectively	174		176		175
Actuarial loss, net of tax of $5,697, $4,668 and $2,879, respectively	8,911		7,301		4,504
Foreign currency translation adjustment	(1,001)		434		(413)
Other comprehensive income (loss)	81,556		(18,514)		(26,231)
Comprehensive income	$ 450,820		$ 339,556		$ 283,382
Basic earnings per share
Income from continuing operations	$ 2.08	[1]	$ 2.12	[1]	$ 1.74	[1]
Income (loss) from discontinued operations	$ 0.00	[1]	$ (0.09)	[1]	$ 0.03	[1]
Net income	$ 2.08	[1]	$ 2.03	[1]	$ 1.76	[1]
Diluted earnings per share
Income from continuing operations	$ 2.06	[1]	$ 2.11	[1]	$ 1.73	[1]
Income (loss) from discontinued operations	$ 0.00	[1]	$ (0.09)	[1]	$ 0.03	[1]
Net income	$ 2.06	[1]	$ 2.01	[1]	$ 1.75	[1]
Average common shares outstanding during the period
Basic	177,814		176,445		175,484
Diluted	179,056		177,671		176,531
Dividends per common share	$ 1.12		$ 0.98		$ 1.13

[1] Amounts may not sum due to rounding.