Employee Benefit Plans (Tables)
 9 Months Ended
Sep. 30, 2016
Compensation and Retirement Disclosure [Abstract]  
Schedule of Defined Benefit Plans Disclosures [Table Text Block]
Contributions to our plans were as follows:
 
Quarter Ended September 30,
 
Nine Months Ended September 30,
(Dollars in millions)
2016
 
2015
 
2016
 
2015
Defined benefit plans
$
18

 
$
23

 
$
125

 
$
93

Defined contribution plans
79

 
82

 
235

 
264


There were no contributions to our domestic defined benefit pension plans in the quarters and nine months ended September 30, 2016 and 2015. The following table illustrates the components of net periodic benefit cost for our defined pension and other postretirement benefit plans:
 
Pension Benefits
Quarter Ended September 30,
 
Other Postretirement Benefits
Quarter Ended September 30,
(Dollars in millions)
2016
 
2015
 
2016
 
2015
Service cost
$
96

 
$
124

 
$
1

 
$
1

Interest cost
302

 
350

 
9

 
8

Expected return on plan assets
(554
)
 
(566
)
 
—

 
—

Amortization of prior service credit
(7
)
 
(3
)
 
—

 
—

Recognized actuarial net loss (gain)
135

 
220

 
(1
)
 
(1
)
Net settlement and curtailment loss
3

 
128

 
—

 
—

Total net periodic benefit (income) cost
$
(25
)
 
$
253

 
$
9

 
$
8


 
Pension Benefits
Nine Months Ended September 30,
 
Other Postretirement Benefits
Nine Months Ended September 30,
(Dollars in millions)
2016
 
2015
 
2016
 
2015
Service cost
$
287

 
$
373

 
$
3

 
$
3

Interest cost
908

 
1,051

 
25

 
24

Expected return on plan assets
(1,669
)
 
(1,700
)
 
—

 
—

Amortization of prior service credit
(22
)
 
(8
)
 
—

 
—

Recognized actuarial net loss (gain)
406

 
662

 
(3
)
 
(3
)
Net settlement and curtailment loss
18

 
137

 
—

 
—

Total net periodic benefit (income) cost
$
(72
)
 
$
515

 
$
25

 
$
24