Quarterly Supplementary Data (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Unaudited Quarterly Financial Information

This table includes unaudited quarterly financial information for the years ended December 31, 2017 and 2016:

(Dollars in millions, except per share data)	Quarter
	1st		2nd		3rd		4th		Full year
2017
Revenues	$	1,523	$	1,386	$	1,412	$	1,411	$	5,732
Income before income taxes	276		128		129		197		730
Net income	201		100		102		642		1,045
Net income per common share—basic	1.22		0.61		0.62		3.92		6.36
Net income per common share—diluted	1.21		0.60		0.61		3.88		6.29
2016
Revenues	$	1,364	$	1,371	$	1,402	$	1,312	$	5,449
Income before income taxes	265		166		253		128		812
Net income	188		123		180		100		591
Net income per common share—basic	1.14		0.75		1.09		0.61		3.59
Net income per common share—diluted	1.13		0.74		1.08		0.60		3.55