Earnings (Loss) Per Share - Summary (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income (loss) attributable to Ingersoll Rand Inc.	$ 29.5	$ 41.3	$ (184.9)	$ 133.4
Average shares outstanding
Basic (shares)	417.6	204.2	370.8	203.1
Diluted (shares)	422.0	209.0	370.8	208.6
Earnings (loss) per share
Basic (USD per share)	$ 0.07	$ 0.20	$ (0.50)	$ 0.66
Diluted (USD per share)	$ 0.07	$ 0.20	$ (0.50)	$ 0.64