XML 67 R55.htm IDEA: XBRL DOCUMENT v3.7.0.1
Notes Payable And Long-term Debt: Schedule of Short-term Debt and Narrative (Details)
6 Months Ended
Aug. 09, 2016
USD ($)
credit_extension
Jun. 30, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 22, 2016
USD ($)
Aug. 08, 2016
USD ($)
Jun. 30, 2016
USD ($)
Short-term Debt [Line Items]            
Notes payable   $ 107,975,000 $ 96,600,000     $ 75,000,000
Letters of Credit   24,540,000 36,000,000     24,700,000
Commercial Paper, Maximum Borrowing Capacity   750,000,000   $ 750,000,000    
Revolving Credit Facility            
Short-term Debt [Line Items]            
Notes payable   0 96,600,000     75,000,000
Letters of Credit   24,540,000 36,000,000     24,700,000
Line of Credit Facility, Current Borrowing Capacity $ 750,000,000       $ 500,000,000  
Number Of One-Year Extension Options | credit_extension 2          
Debt Instrument, Term 1 year          
Line of Credit Facility, Maximum Borrowing Capacity   $ 1,000,000,000        
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage   0.20%        
Revolving Credit Facility | Base Rate            
Short-term Debt [Line Items]            
Line of Credit Facility, Interest Rate at Period End   0.25%        
Revolving Credit Facility | Eurodollar            
Short-term Debt [Line Items]            
Line of Credit Facility, Interest Rate at Period End   1.25%        
Revolving Credit Facility | Letter of Credit            
Short-term Debt [Line Items]            
Line of Credit Facility, Interest Rate at Period End   1.25%        
CP Program            
Short-term Debt [Line Items]            
Notes payable   $ 107,975,000 $ 0     $ 0
Debt Instrument, Term   397 days        
Short-term Debt, Weighted Average Interest Rate   1.41%