SCHEDULE I - BALANCE SHEETS (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current assets [Abstract]
Cash and cash equivalents	$ 1,750.9	$ 505.5
Other current assets	201.0	76.8
Total current assets	3,862.1	1,543.9
Deferred tax assets	16.1	3.0
Total identifiable assets	16,058.6	4,628.4	$ 4,487.1
Liabilities and Stockholders' Equity
Total liabilities	6,869.1	2,758.5
Stockholders' equity [Abstract]
Common stock, $0.01 par value; 1,000,000,000 shares authorized; 420,123,978 and 206,767,529 shares issued as of December 31, 2020 and 2019, respectively	4.2	2.1
Capital in excess of par value	9,310.3	2,302.0
Accumulated deficit	(175.7)	(141.4)
Accumulated other comprehensive income (loss)	14.2	(256.0)
Treasury stock at cost; 1,701,785 and 2,881,436 shares at December 31, 2019 and 2018, respectively	(33.3)	(36.8)
Total Ingersoll Rand Inc. stockholders' equity	9,119.7	1,869.9
Total liabilities and equity	$ 16,058.6	$ 4,628.4
Balance Sheet Related Disclosures [Abstract]
Common stock, par value (USD per share)	$ 0.01	$ 0.01
Common stock authorized (shares)	1,000,000,000	1,000,000,000
Common stock issued (shares)	420,123,978	206,767,529
Treasury stock (shares)	1,496,169	1,701,785
Parent Company
Current assets [Abstract]
Cash and cash equivalents	$ 0.0	$ 0.0
Other current assets	0.4	1.0
Total current assets	0.4	1.0
Equity in net assets of subsidiaries	8,006.0	848.5
Intercompany receivables	1,107.3	1,019.9
Deferred tax assets	10.9	8.3
Total identifiable assets	9,124.6	1,877.7
Liabilities and Stockholders' Equity
Other liabilities	4.9	7.8
Total liabilities	4.9	7.8
Stockholders' equity [Abstract]
Common stock, $0.01 par value; 1,000,000,000 shares authorized; 420,123,978 and 206,767,529 shares issued as of December 31, 2020 and 2019, respectively	4.2	2.1
Capital in excess of par value	9,310.3	2,302.0
Accumulated deficit	(175.7)	(141.4)
Accumulated other comprehensive income (loss)	14.2	(256.0)
Treasury stock at cost; 1,701,785 and 2,881,436 shares at December 31, 2019 and 2018, respectively	(33.3)	(36.8)
Total Ingersoll Rand Inc. stockholders' equity	9,119.7	1,869.9
Total liabilities and equity	$ 9,124.6	$ 1,877.7