Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2023	Apr. 25, 2023
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2023
Document Transition Report	false
Entity File Number	001-16189
Entity Registrant Name	NiSource Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	35-2108964
Entity Address, Address Line One	801 East 86th Avenue
Entity Address, City or Town	Merrillville,
Entity Address, State or Province	IN
Entity Address, Postal Zip Code	46410
City Area Code	(877)
Local Phone Number	647-5990
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		413,063,219
Entity Central Index Key	0001111711
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Amendment Flag	false
Series A Corporate Units
Document Information [Line Items]
Title of 12(b) Security	Series A Corporate Units
Trading Symbol	NIMC
Security Exchange Name	NYSE
Common Stock
Document Information [Line Items]
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	NI
Security Exchange Name	NYSE
Preferred Stock
Document Information [Line Items]
Title of 12(b) Security	Depositary Shares, each representing a 1/1,000th ownership interest in a share of 6.50% Series B Fixed-Rate Reset Cumulative Redeemable Perpetual
Trading Symbol	NI PR B
Security Exchange Name	NYSE