XML 39 R24.htm IDEA: XBRL DOCUMENT v3.8.0.1
Quarterly Financial Data - Unaudited
 12 Months Ended
Dec. 31, 2017
Quaterly Financial Data Unaudited [Abstract]  
Quarterly Financial Information [Text Block]
Quarterly Financial Data—Unaudited
 
Dollars in millions
2017
 
Fourth
 
Third
 
Second
 
First
Revenues
 
$
5,638

 
$
5,314

 
$
5,250

 
$
5,185

Operating income
 
$
2,013

 
$
1,953

 
$
1,787

 
$
1,594

Net income
 
$
8,462

 
$
1,042

 
$
958

 
$
838