Earnings Per Share - Summary (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net income (loss) attributable to Ingersoll Rand Inc.	$ (33.3)	$ 159.1	$ 269.4
Average shares outstanding:
Basic (in shares)	382.8	203.5	201.6
Diluted (in shares)	382.8	208.9	209.1
Earnings (loss) per share:
Basic (USD per share)	$ (0.09)	$ 0.78	$ 1.34
Diluted (USD per share)	$ (0.09)	$ 0.76	$ 1.29