Commitment and Contingencies - Schedule of Estimated Accrued Costs (Details) $ in Millions	3 Months Ended
	Mar. 31, 2022 USD ($)
Minnesota and Indiana Gas Service Territories
Loss Contingencies [Line Items]
Liability recorded for environmental loss contingencies	$ 17
Minnesota and Indiana Gas Service Territories | Minimum
Loss Contingencies [Line Items]
Estimated remediation costs	$ 12
Years to resolve contingency	5 years
Minnesota and Indiana Gas Service Territories | Maximum
Loss Contingencies [Line Items]
Estimated remediation costs	$ 51
Years to resolve contingency	50 years
Minnesota Service Territory | CERC Corp
Loss Contingencies [Line Items]
Liability recorded for environmental loss contingencies	$ 12
Minnesota Service Territory | CERC Corp | Minimum
Loss Contingencies [Line Items]
Estimated remediation costs	$ 9
Years to resolve contingency	30 years
Minnesota Service Territory | CERC Corp | Maximum
Loss Contingencies [Line Items]
Estimated remediation costs	$ 29
Years to resolve contingency	50 years