Investments in Affiliates and Other Related Party Transactions - Beneficial Ownership in Affiliates Accounted for under Equity Method (Detail)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Beijing BHAP Lear Automotive Systems Co., Ltd. (China)
Schedule of Equity Method Investments [Line Items]
Ownership percentage of affiliates	50.00%	50.00%	50.00%
Dong Kwang Lear Yuhan Hoesa (Korea)
Schedule of Equity Method Investments [Line Items]
Ownership percentage of affiliates	50.00%	50.00%	50.00%
Jiangxi Jiangling Lear Interior Systems Co., Ltd. (China)
Schedule of Equity Method Investments [Line Items]
Ownership percentage of affiliates	50.00%	50.00%	50.00%
Lear Dongfeng Automotive Seating Co., Ltd. (China)
Schedule of Equity Method Investments [Line Items]
Ownership percentage of affiliates	50.00%	50.00%	50.00%
Changchun Lear FAWSN Automotive Seat Systems Co., Ltd. (China)
Schedule of Equity Method Investments [Line Items]
Ownership percentage of affiliates	49.00%	49.00%	49.00%
Honduras Electrical Distribution Systems S. de R.L. de C.V. (Honduras)
Schedule of Equity Method Investments [Line Items]
Ownership percentage of affiliates	49.00%	49.00%	49.00%
Kyungshin-Lear Sales and Engineering LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage of affiliates	49.00%	49.00%	49.00%
Beijing Lear Dymos Automotive Systems Co., Ltd. (China)
Schedule of Equity Method Investments [Line Items]
Ownership percentage of affiliates	40.00%	40.00%	40.00%
Dymos Lear Automotive India Private Limited (India)
Schedule of Equity Method Investments [Line Items]
Ownership percentage of affiliates	35.00%	35.00%	35.00%
RevoLaze, LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage of affiliates	20.00%	20.00%	20.00%
Industrias Cousin Freres, S.L. (Spain)
Schedule of Equity Method Investments [Line Items]
Ownership percentage of affiliates	0.00%	50.00%	50.00%
Changchun Lear FAWSN Automotive Electrical and Electronics Co., Ltd. (China)
Schedule of Equity Method Investments [Line Items]
Ownership percentage of affiliates	0.00%	49.00%	49.00%
eLumigen, LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage of affiliates	0.00%	46.00%	46.00%
HB Polymer Company, LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage of affiliates	0.00%	10.00%	10.00%
Shanghai Lear STEC Automotive Parts Co., Ltd. (China)
Schedule of Equity Method Investments [Line Items]
Ownership percentage of affiliates	0.00%	0.00%	55.00%