Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2013

Quarterly Financial Information Disclosure [Abstract]

Schedule of quarterly financial information

	Quarterly Financial Data
	Successor
	First Quarter		Second Quarter	Third Quarter	Fourth Quarter	Twelve Months Total
	(Dollars in millions)
2013
Operating revenues	$	2,159	2,199	2,188	2,207	8,753
Operating income	553		525	493	507	2,078
Income tax expense	166		155	139	142	602
Net income	264		246	218	236	964

	Quarterly Financial Data
	Successor
	First Quarter		Second Quarter	Third Quarter	Fourth Quarter	Twelve Months Total
	(Dollars in millions)
2012
Operating revenues	$	2,260	2,195	2,183	2,210	8,848
Operating income	466		455	459	525	1,905
Income tax expense	136		113	133	160	542
Net income	218		178	212	241	849