XML 72 R59.htm IDEA: XBRL DOCUMENT v3.6.0.2
Benefit Plans and Other Postretirement Benefits, Pension Benefits (Details) - USD ($)
$ in Thousands
1 Months Ended 12 Months Ended
Jan. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Supplemental Executive Retirement Plan (SERP) and Nonqualified Pension Plan        
Pension Benefits [Abstract]        
Total benefit obligation   $ 800 $ 700  
Net benefit cost recognized for financial reporting   7,900 9,500  
Pension Plans        
Defined Benefit Plan Disclosure [Line Items]        
Total contributions to Xcel Energy's pension plans during the period   7,400 4,900 $ 8,000
Pension Benefits [Abstract]        
Total benefit obligation   157,457 152,545 165,669
Net benefit cost recognized for financial reporting   $ 7,579 $ 8,711 $ 8,870
Minimum number of years historical achieved weighted average annual returns are used to determine investment return assumptions (in years)   20 years    
Expected average long-term rate of return on assets (as a percent)   7.10% 7.25% 7.25%
Expected average long-term rate of return on assets for next fiscal year (as a percent)   7.10%    
Target Pension Asset Allocations [Abstract]        
Target pension asset allocations (as a percent)   100.00% 100.00%  
Pension Plans | Domestic and international equity securities        
Target Pension Asset Allocations [Abstract]        
Target pension asset allocations (as a percent)   40.00% 41.00%  
Pension Plans | Long-duration fixed income and interest rate swap securities        
Target Pension Asset Allocations [Abstract]        
Target pension asset allocations (as a percent)   23.00% 23.00%  
Pension Plans | Short-to-intermediate fixed income securities        
Target Pension Asset Allocations [Abstract]        
Target pension asset allocations (as a percent)   16.00% 14.00%  
Pension Plans | Alternative investments        
Target Pension Asset Allocations [Abstract]        
Target pension asset allocations (as a percent)   19.00% 20.00%  
Pension Plans | Cash        
Target Pension Asset Allocations [Abstract]        
Target pension asset allocations (as a percent)   2.00% 2.00%  
Xcel Energy Inc. | Supplemental Executive Retirement Plan (SERP) and Nonqualified Pension Plan        
Pension Benefits [Abstract]        
Total benefit obligation   $ 43,500 $ 41,800  
Xcel Energy Inc. | Pension Plans        
Defined Benefit Plan Disclosure [Line Items]        
Total contributions to Xcel Energy's pension plans during the period   $ 125,200 $ 90,100 $ 130,600
Subsequent Event | Pension Plans        
Defined Benefit Plan Disclosure [Line Items]        
Total contributions to Xcel Energy's pension plans during the period $ 9,000      
Subsequent Event | Xcel Energy Inc. | Pension Plans        
Defined Benefit Plan Disclosure [Line Items]        
Total contributions to Xcel Energy's pension plans during the period $ 150,000