XML 46 R37.htm IDEA: XBRL DOCUMENT v3.22.1
Bilateral Credit Agreement (Details) - Letter of Credit - Bilateral Credit Agreement
$ in Millions
3 Months Ended
Mar. 31, 2022
USD ($)
Short-term Debt [Line Items]  
Borrowing Limit $ 75
Amount outstanding at period end 45
Available $ 30
NSP Minnesota [Member]  
Short-term Debt [Line Items]  
Debt Instrument, Term 1 year