Long-Term Debt	6 Months Ended
Jun. 30, 2013
Long-term Debt, Current and Noncurrent [Abstract]
Long-Term Debt	Long-Term Debt On June 3, 2013, Northern Indiana redeemed $18.0 million of 5.20% pollution control bonds. On April 12, 2013, NiSource Finance issued $750.0 million of 4.80% senior unsecured notes that mature on February 15, 2044. On March 1, 2013, NiSource Finance redeemed $420.3 million of 6.15% senior unsecured notes. On April 5, 2012, NiSource Finance negotiated a $250.0 million three-year bank term loan with a syndicate of banks having an original maturity date of April 3, 2015. On April 15, 2013, NiSource Finance amended the term loan to add an additional lender to the syndicate of banks, increase borrowings under the term loan to $325.0 million and extend the maturity date to April 15, 2016. Borrowings under the term loan have an interest rate of LIBOR plus 125 basis points.

Long-Term Debt

6 Months Ended

Jun. 30, 2013

Long-term Debt, Current and Noncurrent [Abstract]

On June 3, 2013, Northern Indiana redeemed $18.0 million of 5.20% pollution control bonds.

On April 12, 2013, NiSource Finance issued $750.0 million of 4.80% senior unsecured notes that mature on February 15, 2044.

On March 1, 2013, NiSource Finance redeemed $420.3 million of 6.15% senior unsecured notes.

On April 5, 2012, NiSource Finance negotiated a $250.0 million three-year bank term loan with a syndicate of banks having an original maturity date of April 3, 2015. On April 15, 2013, NiSource Finance amended the term loan to add an additional lender to the syndicate of banks, increase borrowings under the term loan to $325.0 million and extend the maturity date to April 15, 2016. Borrowings under the term loan have an interest rate of LIBOR plus 125 basis points.