CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) shares in Millions, $ in Millions		Common Stock [Member]	Capital in Excess of Par Value [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]	Total Ingersoll Rand Inc. Stockholders' Equity	Noncontrolling Interest [Member]	Total
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative-effect adjustment upon adoption of new accounting standard | ASU 2018-02 [Member]	[1]				$ (8.2)
Balance at beginning of period at Dec. 31, 2018		$ 2.0	$ 2,282.7	$ (308.7)	(247.0)	$ (53.0)		$ 0.0
Balance at beginning of period (in shares) at Dec. 31, 2018		201.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchases of treasury stock						(8.5)
Shares issued to acquire Ingersoll Rand Industrial		$ 0.0	0.0
Shares issued to acquire Ingersoll Rand Industrial (in shares)		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
Issuance of common stock for stock-based compensation plans		$ 0.0	12.9
Issuance of common stock for stock-based compensation plans (in shares)		2.2
Issuance of treasury stock for stock-based compensation plans			(9.2)			14.5
Stock-based compensation			2.9
Net (loss) income				47.1				0.0	$ 47.1
Foreign currency translation adjustments, net					(0.1)			0.0	(0.1)
Unrecognized gains on cash flow hedges, net					1.9				1.9
Pension and other postretirement prior service cost and gain or loss, net					0.2				0.2
Noncontrolling interest from acquisition of Ingersoll Rand Industrial								0.0	0.0
Balance at end of period at Mar. 31, 2019		$ 2.0	2,289.3	(253.4)	(253.2)	(47.0)	$ 1,737.7	0.0	1,737.7
Balance at end of period (in shares) at Mar. 31, 2019		203.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative-effect adjustment upon adoption of new accounting standard | ASU 2018-02 [Member]				8.2	(8.2)
Cumulative-effect adjustment upon adoption of new accounting standard | ASU 2016-13 [Member]				0.0
Cumulative-effect adjustment upon adoption of new accounting standard | ASU 2016-13 [Member]				1.0
Balance at beginning of period at Dec. 31, 2019		$ 2.1	2,302.0	(141.4)	(256.0)	(36.8)		0.0	1,869.9
Balance at beginning of period (in shares) at Dec. 31, 2019		206.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchases of treasury stock						(0.8)
Shares issued to acquire Ingersoll Rand Industrial		$ 2.1	6,917.4
Shares issued to acquire Ingersoll Rand Industrial (in shares)		211.0
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)
Issuance of common stock for stock-based compensation plans		$ 0.0	2.2
Issuance of common stock for stock-based compensation plans (in shares)		0.4
Issuance of treasury stock for stock-based compensation plans			(1.0)			1.4
Stock-based compensation			4.4
Net (loss) income				(36.8)				0.0	(36.8)
Foreign currency translation adjustments, net					(92.2)			(4.0)	(92.2)
Unrecognized gains on cash flow hedges, net					1.2				1.2
Pension and other postretirement prior service cost and gain or loss, net					2.9				2.9
Noncontrolling interest from acquisition of Ingersoll Rand Industrial								73.3	0.0
Balance at end of period at Mar. 31, 2020		$ 4.2	$ 9,241.5	(179.2)	(344.1)	$ (36.2)	$ 8,686.2	$ 69.3	$ 8,755.5
Balance at end of period (in shares) at Mar. 31, 2020		418.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative-effect adjustment upon adoption of new accounting standard | ASU 2018-02 [Member]				0.0	$ 0.0
Cumulative-effect adjustment upon adoption of new accounting standard | ASU 2016-13 [Member]				$ (1.0)

[1] All amounts are net of tax.  Amounts in parentheses indicate debits.