Commitments and Contingencies ARO Phantom (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019		Dec. 31, 2018
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation, Liabilities Settled	$ 0.0	[1]	$ 0.0	[2]
Asset Retirement Obligation, Liabilities Incurred	0.0	[1]	0.0	[2]
Electric Plant Electric Distribution
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation, Liabilities Settled	0.0		0.0
Asset Retirement Obligation, Liabilities Incurred	0.0		0.0
Electric Plant Steam Production Asbestos
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation, Liabilities Settled	0.0		0.0
Asset Retirement Obligation, Liabilities Incurred	0.0		0.0
Electric Plant Other
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation, Liabilities Settled	0.0		0.0
Asset Retirement Obligation, Liabilities Incurred	0.0		0.0
Natural Gas Plant Gas Distribution
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation, Liabilities Settled	0.0		0.0
Asset Retirement Obligation, Liabilities Incurred	$ 0.0		$ 0.0

[1] There were no ARO amounts incurred or settled in 2019.

[2] There were no ARO amounts incurred or settled in 2018.