Guarantor Financial Information (Statement of Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Condensed Financial Statements, Captions [Line Items]
Net revenues	$ 519.5	$ 531.5	$ 978.2	$ 998.1
Cost of goods sold	297.7	305.5	569.3	579.9
Selling and administrative expenses	126.1	136.7	242.2	261.1
Operating income	95.7	89.3	166.7	157.1
Equity earnings (loss) in affiliates, net of tax	0.0	0.0	0.0	0.0
Interest expense	11.3	12.5	22.9	25.6
Intercompany interest and fees	0.0	0.0	0.0	0.0
Other (gain) loss, net	0.4	(1.0)	3.5	(1.1)
Earnings before income taxes	84.0	77.8	140.3	132.6
Provision (benefit) for income taxes	19.0	23.1	31.4	39.5
Earnings from continuing operations	65.0	54.7	108.9	93.1
Discontinued operations, net of tax	0.0	(8.0)	(0.2)	(8.8)
Net earnings (loss)	65.0	46.7	108.7	84.3
Less: Net loss attributable to noncontrolling interests	(1.1)	(3.5)	0.6	(5.3)
Net earnings attributable to Allegion plc	63.9	43.2	109.3	79.0
Total comprehensive income	70.5	52.5	83.8	76.1
Less: Total comprehensive income (loss) attributable to noncontrolling interests	1.1	3.5	(0.6)	4.5
Total comprehensive income attributable to Allegion plc	69.4	49.0	84.4	71.6
Other Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net revenues	180.0	221.1	343.9	415.2
Cost of goods sold	127.2	151.3	246.7	287.5
Selling and administrative expenses	46.6	61.6	89.1	115.3
Operating income	6.2	8.2	8.1	12.4
Equity earnings (loss) in affiliates, net of tax	61.5	98.7	109.7	186.1
Interest expense	0.0	0.2	0.1	1.0
Intercompany interest and fees	(13.4)	63.4	(27.7)	126.3
Other (gain) loss, net	0.4	(1.3)	3.4	(1.2)
Earnings before income taxes	80.7	44.6	142.0	72.4
Provision (benefit) for income taxes	(8.9)	(26.8)	(15.9)	(53.6)
Earnings from continuing operations	$ 89.6	71.4	157.9	126.0
Discontinued operations, net of tax		(8.0)	(0.1)	(8.8)
Net earnings (loss)	$ 89.6	63.4	157.8	117.2
Less: Net loss attributable to noncontrolling interests	(1.1)	(3.5)	0.6	(5.3)
Net earnings attributable to Allegion plc	88.5	59.9	158.4	111.9
Total comprehensive income	98.2	63.4	133.6	116.4
Less: Total comprehensive income (loss) attributable to noncontrolling interests	1.1	3.5	(0.6)	4.5
Total comprehensive income attributable to Allegion plc	97.1	59.9	134.2	111.9
Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net revenues	(48.8)	(49.8)	(95.0)	(95.8)
Cost of goods sold	(48.8)	(49.8)	(95.0)	(95.8)
Selling and administrative expenses	0.0	0.0	0.0	0.0
Operating income	0.0	0.0	0.0	0.0
Equity earnings (loss) in affiliates, net of tax	(160.5)	(193.9)	(272.0)	(356.5)
Interest expense	0.0	0.0	0.0	0.0
Intercompany interest and fees	0.0	0.0	0.0	0.0
Other (gain) loss, net	0.0	0.0	0.0	0.0
Earnings before income taxes	(160.5)	(193.9)	(272.0)	(356.5)
Provision (benefit) for income taxes	0.0	0.0	0.0	0.0
Earnings from continuing operations	(160.5)	(193.9)	(272.0)	(356.5)
Discontinued operations, net of tax	0.0	0.0	0.0	0.0
Net earnings (loss)	(160.5)	(193.9)	(272.0)	(356.5)
Less: Net loss attributable to noncontrolling interests	0.0	0.0	0.0	0.0
Net earnings attributable to Allegion plc	(160.5)	(193.9)	(272.0)	(356.5)
Total comprehensive income	(166.2)	(193.9)	(247.1)	(356.5)
Less: Total comprehensive income (loss) attributable to noncontrolling interests	0.0	0.0	0.0	0.0
Total comprehensive income attributable to Allegion plc	(166.2)	(193.9)	(247.1)	(356.5)
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net revenues	0.0	0.0	0.0	0.0
Cost of goods sold	0.0	0.0	0.0	0.0
Selling and administrative expenses	1.1	1.0	2.0	2.0
Operating income	(1.1)	(1.0)	(2.0)	(2.0)
Equity earnings (loss) in affiliates, net of tax	71.1	44.2	123.8	81.0
Interest expense	5.9	0.0	12.4	0.0
Intercompany interest and fees	0.2	0.0	0.2	0.0
Other (gain) loss, net	0.0	0.0	(0.1)	0.0
Earnings before income taxes	63.9	43.2	109.3	79.0
Provision (benefit) for income taxes	0.0	0.0	0.0	0.0
Earnings from continuing operations	63.9	43.2	109.3	79.0
Discontinued operations, net of tax	0.0	0.0	0.0	0.0
Net earnings (loss)	63.9	43.2	109.3	79.0
Less: Net loss attributable to noncontrolling interests	0.0	0.0	0.0	0.0
Net earnings attributable to Allegion plc	63.9	43.2	109.3	79.0
Total comprehensive income	69.4	49.0	84.4	71.6
Less: Total comprehensive income (loss) attributable to noncontrolling interests	0.0	0.0	0.0	0.0
Total comprehensive income attributable to Allegion plc	69.4	49.0	84.4	71.6
Subsidiary Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Net revenues	0.0	0.0	0.0	0.0
Cost of goods sold	0.0	0.0	0.0	0.0
Selling and administrative expenses	0.0	0.0	(0.1)	0.0
Operating income	0.0	0.0	0.1	0.0
Equity earnings (loss) in affiliates, net of tax	27.1	49.5	37.1	87.3
Interest expense	5.4	12.3	10.4	24.6
Intercompany interest and fees	22.8	12.5	46.2	24.9
Other (gain) loss, net	0.0	0.0	(0.2)	0.0
Earnings before income taxes	(1.1)	24.7	(19.2)	37.8
Provision (benefit) for income taxes	(10.8)	(9.3)	(21.7)	(18.6)
Earnings from continuing operations	9.7	34.0	2.5	56.4
Discontinued operations, net of tax	0.0	0.0	0.0	0.0
Net earnings (loss)	9.7	34.0	2.5	56.4
Less: Net loss attributable to noncontrolling interests	0.0	0.0	0.0	0.0
Net earnings attributable to Allegion plc	9.7	34.0	2.5	56.4
Total comprehensive income	10.1	34.0	1.3	56.4
Less: Total comprehensive income (loss) attributable to noncontrolling interests	0.0	0.0	0.0	0.0
Total comprehensive income attributable to Allegion plc	10.1	34.0	1.3	56.4
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net revenues	388.3	360.2	729.3	678.7
Cost of goods sold	219.3	204.0	417.6	388.2
Selling and administrative expenses	78.4	74.1	151.2	143.8
Operating income	90.6	82.1	160.5	146.7
Equity earnings (loss) in affiliates, net of tax	0.8	1.5	1.4	2.1
Interest expense	0.0	0.0	0.0	0.0
Intercompany interest and fees	(9.6)	(75.9)	(18.7)	(151.2)
Other (gain) loss, net	0.0	0.3	0.4	0.1
Earnings before income taxes	101.0	159.2	180.2	299.9
Provision (benefit) for income taxes	38.7	59.2	69.0	111.7
Earnings from continuing operations	62.3	100.0	111.2	188.2
Discontinued operations, net of tax	0.0	0.0	(0.1)	0.0
Net earnings (loss)	62.3	100.0	111.1	188.2
Less: Net loss attributable to noncontrolling interests	0.0	0.0	0.0	0.0
Net earnings attributable to Allegion plc	62.3	100.0	111.1	188.2
Total comprehensive income	59.0	100.0	111.6	188.2
Less: Total comprehensive income (loss) attributable to noncontrolling interests	0.0	0.0	0.0	0.0
Total comprehensive income attributable to Allegion plc	$ 59.0	$ 100.0	$ 111.6	$ 188.2