BUSINESS SEGMENT INFORMATION - Summary (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended		24 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Mar. 31, 2022
Segment Reporting Information, Profit (Loss) [Abstract]
Net sales	$ 4,843	$ 4,692
Interest expense - net	(32)	(38)
Pension and other postretirement benefits income	(6)	(14)
Restructuring program charges	(18)	(16)	$ (78)	$ (214)	$ (310)
Other expense - net	8	11
Income before income taxes	619	538
Income tax expense	86	79
Net income	533	459
Less net income for noncontrolling interests	(1)	(1)
Net income attributable to Eaton ordinary shareholders	532	458
Electrical Americas
Segment Reporting Information, Profit (Loss) [Abstract]
Net sales	1,891	1,622
Electrical Global
Segment Reporting Information, Profit (Loss) [Abstract]
Net sales	1,437	1,253
Hydraulics
Segment Reporting Information, Profit (Loss) [Abstract]
Net sales	0	561
Aerospace
Segment Reporting Information, Profit (Loss) [Abstract]
Net sales	718	519
Vehicle
Segment Reporting Information, Profit (Loss) [Abstract]
Net sales	671	654
eMobility
Segment Reporting Information, Profit (Loss) [Abstract]
Net sales	126	83
Operating segments
Segment Reporting Information, Profit (Loss) [Abstract]
Net sales	4,843	4,692
Segment operating profit (loss)	909	831
Operating segments | Electrical Americas
Segment Reporting Information, Profit (Loss) [Abstract]
Net sales	1,891	1,622
Segment operating profit (loss)	361	332
Restructuring program charges	(5)	(5)
Operating segments | Electrical Global
Segment Reporting Information, Profit (Loss) [Abstract]
Net sales	1,437	1,253
Segment operating profit (loss)	279	213
Restructuring program charges	(5)	(2)
Operating segments | Hydraulics
Segment Reporting Information, Profit (Loss) [Abstract]
Net sales	0	561
Segment operating profit (loss)	0	84
Operating segments | Aerospace
Segment Reporting Information, Profit (Loss) [Abstract]
Net sales	718	519
Segment operating profit (loss)	159	96
Restructuring program charges	(3)	(1)
Operating segments | Vehicle
Segment Reporting Information, Profit (Loss) [Abstract]
Net sales	671	654
Segment operating profit (loss)	113	113
Restructuring program charges	(3)	(6)
Operating segments | eMobility
Segment Reporting Information, Profit (Loss) [Abstract]
Net sales	126	83
Segment operating profit (loss)	(3)	(7)
Corporate
Segment Reporting Information, Profit (Loss) [Abstract]
Intangible asset amortization expense	(128)	(92)
Interest expense - net	(32)	(38)
Pension and other postretirement benefits income	19	14
Restructuring program charges	(2)	(2)
Other expense - net	$ (131)	$ (161)