Long-Term Debt	3 Months Ended
Mar. 31, 2017
Long-term Debt, Current and Noncurrent [Abstract]
Long-term Debt	Long-Term Debt NiSource Finance is a 100% owned, consolidated finance subsidiary of NiSource that engages in financing activities to raise funds for the business operations of NiSource and its subsidiaries. NiSource Finance was incorporated in March 2000 under the laws of the state of Indiana. Prior to 2000, the function of NiSource Finance was performed by Capital Markets. NiSource Finance obligations are fully and unconditionally guaranteed by NiSource. Consequently, no separate financial statements for NiSource Finance are required to be reported. No NiSource subsidiaries guarantee debt. NiSource announced on April 26, 2017, that it intends to merge NiSource Finance and Capital Markets into NiSource during the second half of 2017, pending receipt of applicable approvals. Upon completion of the mergers, NiSource will become the primary obligor of NiSource Finance's and Capital Markets' outstanding obligations. The mergers are not expected to have any impact on NiSource's consolidated financial statements or the credit ratings of outstanding debt securities. On March 27, 2017, Capital Markets redeemed $30.0 million of 7.86% and $2.0 million of 7.85% medium term notes at maturity. On April 3, 2017, Capital Markets redeemed $12.0 million of 7.82%, $10.0 million of 7.92%, $2.0 million of 7.93% and $1.0 million of 7.94% medium term notes at maturity.

Long-Term Debt

NiSource Finance is a 100% owned, consolidated finance subsidiary of NiSource that engages in financing activities to raise funds for the business operations of NiSource and its subsidiaries. NiSource Finance was incorporated in March 2000 under the laws of the state of Indiana. Prior to 2000, the function of NiSource Finance was performed by Capital Markets. NiSource Finance obligations are fully and unconditionally guaranteed by NiSource. Consequently, no separate financial statements for NiSource Finance are required to be reported. No NiSource subsidiaries guarantee debt.

NiSource announced on April 26, 2017, that it intends to merge NiSource Finance and Capital Markets into NiSource during the second half of 2017, pending receipt of applicable approvals. Upon completion of the mergers, NiSource will become the primary obligor of NiSource Finance's and Capital Markets' outstanding obligations. The mergers are not expected to have any impact on NiSource's consolidated financial statements or the credit ratings of outstanding debt securities.

On March 27, 2017, Capital Markets redeemed $30.0 million of 7.86% and $2.0 million of 7.85% medium term notes at maturity.

On April 3, 2017, Capital Markets redeemed $12.0 million of 7.82%, $10.0 million of 7.92%, $2.0 million of 7.93% and $1.0 million of 7.94% medium term notes at maturity.