Organization and Nature of Operations (Details)	12 Months Ended
	Dec. 31, 2017 customer business_area public_utility
Public Utilities, General Disclosures [Line Items]
Number of public utility subsidiaries owned by wholly owned subsidiary, Vectren Utility Holdings, Inc. (in number of subsidiaries) | public_utility	3
Number of primary business areas | business_area	2
Natural Gas Customers | INDIANA | Indiana Gas
Public Utilities, General Disclosures [Line Items]
Approximate number of customers	592,400
Natural Gas Customers | INDIANA | SIGECO
Public Utilities, General Disclosures [Line Items]
Approximate number of customers	111,500
Natural Gas Customers | OHIO | Vectren Energy Delivery of Ohio
Public Utilities, General Disclosures [Line Items]
Approximate number of customers	318,100
Electric Customers | INDIANA | SIGECO
Public Utilities, General Disclosures [Line Items]
Approximate number of customers	145,200