Legal Proceedings, Contingencies and Commitments (Tables)
6 Months Ended 12 Months Ended
Jun. 30, 2016
Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]    
Schedule of Significant Commitments  
A summary of the contractual amount of significant commitments is as follows. 
 
December 31,
 
2015
 
2014
 
(Dollars in millions)
Commitments to extend credit
 
 
 
Mortgage loans interest-rate lock commitments
$
3,792

 
$
2,172

HELOC commitments
150

 
88

Other consumer commitments
22

 
7

Warehouse loan commitments
871

 
827

Standby and commercial letters of credit
13

 
10

Commercial and industrial commitments
151

 
276

Other commercial commitments
497

 
169


Other Commitments
A summary of the contractual amount of significant commitments is as follows:
 
June 30, 2016
 
December 31, 2015
 
(Dollars in millions)
Commitments to extend credit
 
 
 
Mortgage loans interest-rate lock commitments
$
6,398

 
$
3,792

HELOC commitments
161

 
150

Other consumer commitments
33

 
22

Warehouse loan commitments
779

 
871

Standby and commercial letters of credit
18

 
13

Commercial and industrial commitments
157

 
151

Other commercial commitments
723

 
497