Organization and Basis of Presentation - Summary of Major Subsidiaries VIEs and VIEs' Subsidiaries (Details)	12 Months Ended
	Dec. 31, 2021
Schedule of Subsidiaries, Variable Interest Entities (VIEs) and VIEs Subsidiaries [Line Items]
Place of establishment	E9
Sunlands Online Education HK Limited ("Sunlands HK")
Schedule of Subsidiaries, Variable Interest Entities (VIEs) and VIEs Subsidiaries [Line Items]
Date of establishment/ acquisition	Oct. 06, 2015
Place of establishment	K3
Percentage of direct or indirect economic ownership	100.00%
Principal activities	Investment holding
Wuhan Studyvip Online Education Co., Ltd. ("Wuhan Zhibo")
Schedule of Subsidiaries, Variable Interest Entities (VIEs) and VIEs Subsidiaries [Line Items]
Date of establishment/ acquisition	Aug. 02, 2017
Place of establishment	F4
Percentage of direct or indirect economic ownership	100.00%
Principal activities	Provision of technical consultation and services
Tianjin Alaman Education Technology Co., Ltd. ("Tianjin Alaman")
Schedule of Subsidiaries, Variable Interest Entities (VIEs) and VIEs Subsidiaries [Line Items]
Date of establishment/ acquisition	Jul. 31, 2017
Place of establishment	F4
Percentage of direct or indirect economic ownership	100.00%
Principal activities	Provision of technical consultation and services
Wuhan Shangde Online Education Technology Co., Ltd. ("Wuhan Shangde")
Schedule of Subsidiaries, Variable Interest Entities (VIEs) and VIEs Subsidiaries [Line Items]
Date of establishment/ acquisition	Jun. 25, 2019
Place of establishment	F4
Percentage of direct or indirect economic ownership	100.00%
Principal activities	Provision of education services
Beijing Sunlands Online Education Technology Co., Ltd. ("Beijing Sunlands")
Schedule of Subsidiaries, Variable Interest Entities (VIEs) and VIEs Subsidiaries [Line Items]
Date of establishment/ acquisition	Sep. 27, 2013
Place of establishment	F4
Principal activities	Investment holding and provision of education services
Tianjin Shangde Online Education Technology Co., Ltd. ("Tianjin Shangde")
Schedule of Subsidiaries, Variable Interest Entities (VIEs) and VIEs Subsidiaries [Line Items]
Date of establishment/ acquisition	Mar. 21, 2018
Place of establishment	F4
Principal activities	Provision of education services
Wuhan Jiayan Online Education Technology Co., Ltd. ("Wuhan Jiayan")
Schedule of Subsidiaries, Variable Interest Entities (VIEs) and VIEs Subsidiaries [Line Items]
Date of establishment/ acquisition	Aug. 05, 2020
Place of establishment	F4
Principal activities	Provision of education services
Beijing Baobian Consumer Technology Co., Ltd.
Schedule of Subsidiaries, Variable Interest Entities (VIEs) and VIEs Subsidiaries [Line Items]
Date of establishment/ acquisition	Mar. 13, 2012
Place of establishment	F4
Principal activities	Provision of education, consumer and technology services
Beijing Shangren Chongye Education Technology Co., Ltd.
Schedule of Subsidiaries, Variable Interest Entities (VIEs) and VIEs Subsidiaries [Line Items]
Date of establishment/ acquisition	Sep. 27, 2013
Place of establishment	F4
Principal activities	Provision of education services
Beijing Jiayan Online Education Technology Co., Ltd.
Schedule of Subsidiaries, Variable Interest Entities (VIEs) and VIEs Subsidiaries [Line Items]
Date of establishment/ acquisition	Aug. 26, 2020
Place of establishment	F4
Principal activities	Provision of education services