v3.3.1.900
Commitments and Contingencies (Tables)
 12 Months Ended
Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]  
Schedule of Commitments
Future minimum annual payments applicable to all non-cancellable operating leases and purchase obligations as of December 31, 2015, are as follows (in millions):
 
Payments Due by Period
 
2016
 
2017
 
2018
 
2019
 
2020
 
Thereafter
 
Total
Operating leases
$
12

 
$
10

 
$
9

 
$
8

 
$
7

 
$
63

 
$
109

Purchase obligations
85

 
84

 
84

 
84

 
84

 
61

 
482

Total
$
97

 
$
94

 
$
93

 
$
92

 
$
91

 
$
124

 
$
591
Environmental Liabilities
Changes in our environmental liabilities for the years ended December 31, 2015 and 2014, were as follows (in millions):
 
Tioga Crude Oil Pipeline Release
 
Other Liabilities
 
Total
Balance at December 31, 2014
$
25

 
$
7

 
$
32

Additions
24

 
1

 
25

Expenditures
(22
)
 
(2
)
 
(24
)
Balance at December 31, 2015
$
27

 
$
6

 
$
33