Cover Page - shares	3 Months Ended
	Mar. 31, 2024	Apr. 23, 2024
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	001-36129
Entity Registrant Name	ONEMAIN HOLDINGS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-3379612
Entity Address, Address Line One	601 N.W. Second Street
Entity Address, City or Town	Evansville
Entity Address, State or Province	IN
Entity Address, Postal Zip Code	47708
City Area Code	812
Local Phone Number	424-8031
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	OMF
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		119,808,695
Entity Central Index Key	0001584207
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
OMFC
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	001-06155
Entity Registrant Name	ONEMAIN FINANCE CORPORATION
Entity Incorporation, State or Country Code	IN
Entity Tax Identification Number	35-0416090
Entity Address, Address Line One	601 N.W. Second Street
Entity Address, City or Town	Evansville
Entity Address, State or Province	IN
Entity Address, Postal Zip Code	47708
City Area Code	812
Local Phone Number	424-8031
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		10,160,021
Entity Central Index Key	0000025598
Amendment Flag	false
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1