Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Data (Unaudited)

Quarterly Financial Data (Unaudited)

	First Quarter		Second Quarter	Third Quarter	Fourth Quarter		Total
	(Dollars in millions)
2017
Operating revenues	$	2,162	2,133	2,141	2,114		8,550
Operating income	580		573	560	600		2,313
Income tax expense (benefit)	174		170	168	(378	)	134
Net income	278		268	265	846		1,657

	First Quarter		Second Quarter	Third Quarter	Fourth Quarter	Total
	(Dollars in millions)
2016
Operating revenues	$	2,253	2,223	2,226	2,208	8,910
Operating income	625		602	576	521	2,324
Income tax expense	188		179	159	152	678
Net income	304		288	255	238	1,085

In the fourth quarter of 2017, we recognized a tax benefit of $555 million due to the change in the federal corporate tax rate from 35% to 21%. During the fourth quarter of 2016, we recognized $78 million of severance expenses and other one-time termination benefits associated with workforce reductions.