CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Capital in Excess of Par Value	Accumulated Deficit	Accumulated Deficit Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Cumulative Effect, Period of Adoption, Adjustment	Treasury Stock	Total Ingersoll Rand Inc. Stockholders' Equity	Noncontrolling Interests
Balance at beginning of period (shares) at Dec. 31, 2018		201.1
Balance at beginning of period at Dec. 31, 2018		$ 2.0	$ 2,282.7	$ (308.7)		$ (247.0)	$ (8.2)	$ (53.0)		$ 0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchases of treasury stock								(17.3)
Issuance of common stock for stock-based compensation plans (shares)		5.1
Issuance of common stock for stock-based compensation plans		$ 0.1	29.4
Issuance of treasury stock for stock-based compensation plans			(25.9)					34.0
Shares issued to acquire Ingersoll Rand Industrial (shares)		0.0
Shares issued to acquire Ingersoll Rand Industrial		$ 0.0	0.0
Fair value attributable to pre-merger service for replacement equity awards			0.0
Fair value attributable to pre-merger service for deferred compensation plan			0.0
Cost incurred to issue shares for Ingersoll Rand Industrial acquisition			0.0
Stock-based compensation			8.1
Noncontrolling interest from acquisition of Ingersoll Rand Industrial										0.0
Net income	$ 133.4			133.4						0.0
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201802Member
Foreign currency translation adjustments, net						(55.3)				0.0
Unrecognized gains on cash flow hedges, net	$ 4.7					4.7
Pension and other postretirement prior service cost and gain or loss, net	3.3					3.3
Acquisition of noncontrolling interests (Note 19)										0.0
Balance at end of period at Sep. 30, 2019	1,790.5	$ 2.1	2,294.3	(167.1)		(302.5)		(36.3)	$ 1,790.5	0.0
Balance at end of period (Accounting Standards Update 2018-02) at Sep. 30, 2019					$ 8.2		(8.2)
Balance at end of period (Accounting Standards Update 2016-13) at Sep. 30, 2019					0.0
Balance at end of period (shares) at Sep. 30, 2019		206.2
Balance at beginning of period (shares) at Jun. 30, 2019		205.7
Balance at beginning of period at Jun. 30, 2019		$ 2.1	2,287.9	(208.4)		(258.9)		(37.4)		0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchases of treasury stock								(0.1)
Issuance of common stock for stock-based compensation plans (shares)		0.5
Issuance of common stock for stock-based compensation plans		$ 0.0	4.7
Issuance of treasury stock for stock-based compensation plans			(0.7)					1.2
Stock-based compensation			2.4
Net income	41.3			41.3						0.0
Foreign currency translation adjustments, net						(48.8)				0.0
Unrecognized gains on cash flow hedges, net	3.3					3.3
Pension and other postretirement prior service cost and gain or loss, net	1.9					1.9
Acquisition of noncontrolling interests (Note 19)										0.0
Balance at end of period at Sep. 30, 2019	1,790.5	$ 2.1	2,294.3	(167.1)		(302.5)		(36.3)	1,790.5	0.0
Balance at end of period (Accounting Standards Update 2018-02) at Sep. 30, 2019					8.2		(8.2)
Balance at end of period (Accounting Standards Update 2016-13) at Sep. 30, 2019					0.0
Balance at end of period (shares) at Sep. 30, 2019		206.2
Balance at beginning of period (shares) at Dec. 31, 2019		206.8
Balance at beginning of period at Dec. 31, 2019	1,869.9	$ 2.1	2,302.0	(141.4)		(256.0)		(36.8)		0.0
Balance at beginning of period (Accounting Standards Update 2016-13) at Dec. 31, 2019					(1.0)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchases of treasury stock								(1.4)
Issuance of common stock for stock-based compensation plans (shares)		1.4
Issuance of common stock for stock-based compensation plans		$ 0.0	11.4
Issuance of treasury stock for stock-based compensation plans			(2.2)					3.4
Shares issued to acquire Ingersoll Rand Industrial (shares)		211.0
Shares issued to acquire Ingersoll Rand Industrial		$ 2.1	6,917.4
Fair value attributable to pre-merger service for replacement equity awards			8.6
Fair value attributable to pre-merger service for deferred compensation plan			8.9
Cost incurred to issue shares for Ingersoll Rand Industrial acquisition			(1.0)
Stock-based compensation			31.9
Noncontrolling interest from acquisition of Ingersoll Rand Industrial										73.3
Net income	$ (184.9)			(184.9)						1.4
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Foreign currency translation adjustments, net						95.3				(1.6)
Unrecognized gains on cash flow hedges, net	$ 10.9					10.9
Pension and other postretirement prior service cost and gain or loss, net	2.4					2.4
Acquisition of noncontrolling interests (Note 19)										(14.9)
Balance at end of period at Sep. 30, 2020	8,829.9	$ 4.2	9,277.0	(327.3)		(147.4)		(34.8)	8,771.7	58.2
Balance at end of period (Accounting Standards Update 2018-02) at Sep. 30, 2020					0.0		0.0
Balance at end of period (Accounting Standards Update 2016-13) at Sep. 30, 2020					(1.0)
Balance at end of period (shares) at Sep. 30, 2020		419.2
Balance at beginning of period (shares) at Jun. 30, 2020		418.6
Balance at beginning of period at Jun. 30, 2020		$ 4.2	9,256.5	(356.8)		(293.2)		(35.8)		66.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchases of treasury stock								(0.1)
Issuance of common stock for stock-based compensation plans (shares)		0.6
Issuance of common stock for stock-based compensation plans		$ 0.0	5.5
Issuance of treasury stock for stock-based compensation plans			(0.7)					1.1
Stock-based compensation			15.7
Net income	29.5			29.5						0.4
Foreign currency translation adjustments, net						142.6				3.8
Unrecognized gains on cash flow hedges, net	4.2					4.2
Pension and other postretirement prior service cost and gain or loss, net	(1.0)					(1.0)
Acquisition of noncontrolling interests (Note 19)										(12.9)
Balance at end of period at Sep. 30, 2020	$ 8,829.9	$ 4.2	$ 9,277.0	$ (327.3)		$ (147.4)		$ (34.8)	$ 8,771.7	$ 58.2
Balance at end of period (Accounting Standards Update 2018-02) at Sep. 30, 2020					0.0		$ 0.0
Balance at end of period (Accounting Standards Update 2016-13) at Sep. 30, 2020					$ (1.0)
Balance at end of period (shares) at Sep. 30, 2020		419.2