Summary of Significant Accounting Policies Operating Revenues (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) performance_obligations contract	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Electric
Disaggregation of Operating Revenues
Number of days payment is due	30 days
Electric | Retail
Disaggregation of Operating Revenues
Number of performance obligations	1
Percent fuel and purchased power costs can vary from the rate case approved costs before deferral is required	2.00%
Electric | Wholesale
Disaggregation of Operating Revenues
Number of performance obligations	2
Number of contracts | contract	1
Natural gas
Disaggregation of Operating Revenues
Number of days payment is due	30 days
Other non-utility revenues
Disaggregation of Operating Revenues
Number of days payment is due	30 days
Other non-utility revenues | We Power revenues
Disaggregation of Operating Revenues
Revenues amortized from deferred revenue during the period | $	$ 23.3	$ 22.9	$ 25.4
Other non-utility revenues | Appliance service repairs | Maximum
Disaggregation of Operating Revenues
Duration of contract for remaining performance obligations in contract	1 year