Rendering

Component: (Network and Table)
Network
2402406 - Disclosure - Significant Accounting Policies Other Noncurrent Liabilities (Details)
(http://www.northwesternenergy.com/role/SignificantAccountingPoliciesOtherNoncurrentLiabilitiesDetails)
Table(Implied)
Slicers (applies to each fact value in each table cell)
Reporting Entity [Axis]0000073088 (http://www.sec.gov/CIK)
Accounting Policies [Abstract]Period [Axis]
2016-12-31
2015-12-31
2014-12-31
Accounting Policies [Abstract]
 
 
 
Future QF obligation, net
134,324,000  
138,310,000  
 
Pension and other employee benefits
120,122,000  
131,887,000  
 
Environmental
30,501,000  
30,226,000  
 
Customer advances
40,209,000  
36,046,000  
 
Asset retirement obligations
39,402,000  
35,532,000  
21,435,000  
Other
55,213,000  
46,569,000  
 
Total
419,771,000  
 
418,570,000