Business Combinations - Preliminary Purchase Price Allocation (Details) - USD ($) $ / shares in Units, $ in Millions				7 Months Ended
	Sep. 30, 2020	Feb. 29, 2020	Feb. 28, 2020	Sep. 30, 2020	Dec. 31, 2019
Estimated Fair Value [Abstract]
Property, plant and equipment		$ 518.7
Goodwill	$ 6,205.7			$ 6,205.7	$ 1,287.7
Ingersoll Rand Industrial
Purchase Price [Abstract]
Fair value of Ingersoll Rand common stock issued for Ingersoll Rand Industrial outstanding common stock	6,919.5	6,919.5		6,919.5
Fair value attributable to pre-merger service for replacement equity awards	8.6	8.6
Fair value attributable to pre-merger service for deferred compensation plan	8.9	8.9
Total purchase consideration	6,937.0	6,937.0
Estimated Fair Value [Abstract]
Cash	38.8	41.3		38.8
Accounts receivable	585.6	579.9		585.6
Inventories	636.2	576.2		636.2
Other current assets	116.2	136.9		116.2
Property, plant and equipment	518.7	520.0		518.7
Goodwill	4,861.8	4,278.2		4,861.8
Intangible assets	3,766.6	4,501.3		3,766.6
Other noncurrent assets	261.6	269.8		261.6
Total current liabilities, including current maturities of long-term debt of $19.0 million	(773.0)	(830.6)		(773.0)
Deferred tax liability	(849.3)	(900.6)		(849.3)
Long-term debt, net of debt issuance costs and an original issue discount	(1,851.7)	(1,851.7)		(1,851.7)
Other noncurrent liabilities	(301.2)	(310.4)		(301.2)
Noncontrolling interest	(73.3)	(73.3)		(73.3)
Total purchase price allocation	$ 6,937.0	$ 6,937.0		6,937.0
Measurement Period Adjustments [Abstract]
Cash				(2.5)
Accounts receivable				5.7
Inventories				60.0
Other current assets				(20.7)
Property, plant and equipment				(1.3)
Goodwill				583.6
Intangible assets				(734.7)
Other noncurrent assets				(8.2)
Total current liabilities, including current maturities of long-term debt of $19.0 million				57.6
Deferred tax liability				51.3
Other noncurrent liabilities				$ 9.2
Current maturities of long-term debt			$ 19.0
Fair value of stock issued (shares)			211,023,522
Closing price per share (USD per share)			$ 32.79