CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Millions, $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Total Ingersoll Rand Inc. Stockholders' Equity	Total Ingersoll Rand Inc. Stockholders' Equity Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Capital in Excess of Par Value	Retained Earnings (Accumulated Deficit)	Retained Earnings (Accumulated Deficit) Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Noncontrolling Interests
Balance at beginning of period (in shares) at Dec. 31, 2019					206.8
Balance at beginning of period at Dec. 31, 2019	$ 1,869.9	$ (1.0)	$ 1,869.9	$ (1.0)	$ 2.1	$ 2,302.0	$ (141.4)	$ (1.0)	$ (256.0)	$ (36.8)	$ 0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	(183.5)		(184.9)				(184.9)				1.4
Acquisition of Ingersoll Rand Industrial (in shares)					211.0
Acquisition of Ingersoll Rand Industrial	7,010.3		6,937.0		$ 2.1	6,934.9					73.3
Costs of issuing equity securities	(1.0)		(1.0)			(1.0)
Issuance of common stock for stock-based compensation plans (in shares)					1.4
Issuance of common stock for stock-based compensation plans	11.4		11.4			11.4
Purchases of treasury stock	(1.4)		(1.4)							(1.4)
Issuance of treasury stock for stock-based compensation plans	1.2		1.2			(2.2)				3.4
Stock-based compensation	31.9		31.9			31.9
Other comprehensive income (loss), net of tax	107.0		108.6						108.6		(1.6)
Adjustments for shares tendered in open offer	(14.9)										(14.9)
Balance at end of period (in shares) at Sep. 30, 2020					419.2
Balance at end of period at Sep. 30, 2020	8,829.9		8,771.7		$ 4.2	9,277.0	(327.3)		(147.4)	(34.8)	58.2
Balance at beginning of period (in shares) at Jun. 30, 2020					418.6
Balance at beginning of period at Jun. 30, 2020	8,641.8		8,574.9		$ 4.2	9,256.5	(356.8)		(293.2)	(35.8)	66.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	29.9		29.5				29.5				0.4
Issuance of common stock for stock-based compensation plans (in shares)					0.6
Issuance of common stock for stock-based compensation plans	5.5		5.5			5.5
Purchases of treasury stock	(0.1)		(0.1)							(0.1)
Issuance of treasury stock for stock-based compensation plans	0.4		0.4			(0.7)				1.1
Stock-based compensation	15.7		15.7			15.7
Other comprehensive income (loss), net of tax	149.6		145.8						145.8		3.8
Adjustments for shares tendered in open offer	(12.9)										(12.9)
Balance at end of period (in shares) at Sep. 30, 2020					419.2
Balance at end of period at Sep. 30, 2020	8,829.9		8,771.7		$ 4.2	9,277.0	(327.3)		(147.4)	(34.8)	58.2
Balance at beginning of period (in shares) at Dec. 31, 2020					420.1
Balance at beginning of period at Dec. 31, 2020	9,189.5		9,119.7		$ 4.2	9,310.3	(175.7)		14.2	(33.3)	69.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	271.3		269.5				269.5				1.8
Issuance of common stock for stock-based compensation plans (in shares)					3.4
Issuance of common stock for stock-based compensation plans	19.0		19.0			19.0
Purchases of treasury stock	(736.5)		(736.5)							(736.5)
Issuance of treasury stock for stock-based compensation plans	0.8		0.8			(19.4)				20.2
Stock-based compensation	76.6		76.6			76.6
Other comprehensive income (loss), net of tax	(96.1)		(94.0)						(94.0)		(2.1)
Divestiture of foreign subsidiaries	(1.5)		(1.5)						(1.5)
Dividends attributable to noncontrolling interests	(0.3)										(0.3)
Balance at end of period (in shares) at Sep. 30, 2021					423.5
Balance at end of period at Sep. 30, 2021	8,722.8		8,653.6		$ 4.2	9,386.5	93.8		(81.3)	(749.6)	69.2
Balance at beginning of period (in shares) at Jun. 30, 2021					421.5
Balance at beginning of period at Jun. 30, 2021	9,346.4		9,277.9		$ 4.2	9,376.0	(32.2)		(35.5)	(34.6)	68.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	126.8		126.0				126.0				0.8
Issuance of common stock for stock-based compensation plans (in shares)					2.0
Issuance of common stock for stock-based compensation plans	6.7		6.7			6.7
Purchases of treasury stock	(733.3)		(733.3)							(733.3)
Issuance of treasury stock for stock-based compensation plans	0.0					(18.3)				18.3
Stock-based compensation	22.1		22.1			22.1
Other comprehensive income (loss), net of tax	(45.6)		(45.8)						(45.8)		0.2
Dividends attributable to noncontrolling interests	(0.3)										(0.3)
Balance at end of period (in shares) at Sep. 30, 2021					423.5
Balance at end of period at Sep. 30, 2021	$ 8,722.8		$ 8,653.6		$ 4.2	$ 9,386.5	$ 93.8		$ (81.3)	$ (749.6)	$ 69.2