Quarterly Results (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2014

Quarterly Results (Unaudited) [Abstract]

Schedule Of Quarterly Financial Information

	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
	(in millions, except per share amounts)
	2014
Operating revenues	$	1,113	$	1,035	$	928	$	962
Operating income		435		367		286		285
Net income		194		207		211		312
Earnings per share - Basic		0.55		0.59		0.60		0.89
Earnings per share - Diluted		0.55		0.59		0.60		0.88
	2013
Operating revenues	$	734	$	862	$	868	$	907
Operating income		252		325		309		317
Net income		128		246		186		144
Earnings per share - Basic		0.36		0.70		0.53		0.41
Earnings per share - Diluted		0.36		0.70		0.53		0.41