Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2012

Selected Quarterly Financial Data (Unaudited)

Schedule of quarterly financial information

Consolidated quarterly financial information for 2012 and 2011 is as follows (dollars in thousands, except per share amounts):

	2012 Quarter Ended									2012
	March 31,			June 30,		Sept. 30,		Dec. 31,		Total
Operating revenues	$	620,631		$	878,576	$	1,109,475	$	693,122	$	3,301,804
Operations and maintenance	210,663			216,236		220,729		237,141		884,769
Operating income	48,007			254,489		447,970		101,289		851,755
Income taxes	(4,645		)	76,689		147,116		18,157		237,317
Income from continuing operations	284			130,930		252,874		34,905		418,993
Net income (loss) attributable to common shareholders	(8,257		)	122,345		244,823		22,631		381,542
Earnings Per Share:
Income (loss) from continuing operations attributable to common shareholders — Basic	$	(0.07	)	$	1.12	$	2.23	$	0.24	$	3.54
Net income (loss) attributable to common shareholders — Basic	(0.08		)	1.12		2.23		0.21		3.48
Income (loss) from continuing operations attributable to common shareholders — Diluted	(0.07		)	1.12		2.21		0.24		3.50
Net income (loss) attributable to common shareholders — Diluted	(0.08		)	1.11		2.21		0.20		3.45

	2011 Quarter Ended									2011
	March 31,			June 30,		Sept. 30,		Dec. 31,		Total
Operating revenues	$	648,847		$	799,799	$	1,124,841	$	667,892	$	3,241,379
Operations and maintenance	255,029			210,590		210,035		228,632		904,286
Operating income	35,784			196,992		435,017		78,715		746,508
Income taxes	(6,005		)	50,818		131,416		7,375		183,604
Income (loss) from continuing operations	(10,368		)	93,185		253,273		19,544		355,634
Net income (loss) attributable to common shareholders	(15,135		)	86,685		255,359		12,564		339,473
Earnings Per Share:
Income (loss) from continuing operations attributable to common shareholders — Basic	$	(0.15	)	$	0.79	$	2.25	$	0.11	$	3.01
Net income (loss) attributable to common shareholders — Basic	(0.14		)	0.80		2.34		0.12		3.11
Income (loss) from continuing operations attributable to common shareholders — Diluted	(0.15		)	0.78		2.24		0.11		2.99
Net income (loss) attributable to common shareholders — Diluted	(0.14		)	0.79		2.32		0.11		3.09