Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Income Statement [Abstract]
Revenues	$ 1,072.7	$ 965.9
Operating expenses:
Cost of revenues (excluding depreciation and amortization shown separately below)	475.0	430.8
Selling, general and administrative expenses	396.1	371.7
Depreciation and amortization	153.7	148.5
Impairment of long-lived assets	0.0	0.7
Restructuring costs	64.9	4.6
Other operating income, net	(6.8)	(6.1)
Total operating expenses	1,082.9	950.2
Operating (loss) income	(10.2)	15.7
Interest expense, net	(58.5)	(83.5)
Foreign currency exchange gain, net	5.6	32.0
Nonoperating expense, net	0.0	(58.8)
Loss before income taxes	(63.1)	(94.6)
Income tax expense	(25.6)	(23.3)
Net loss	(88.7)	(117.9)
Less: Net income attributable to noncontrolling interests	1.4	1.9
Net loss attributable to NIQ	$ (90.1)	$ (119.8)
Basic and diluted earnings per share from:
Net loss attributable to NIQ, basic (in dollars per share)	$ (0.31)	$ (0.49)
Net loss attributable to NIQ, diluted (in dollars per share)	$ (0.31)	$ (0.49)
Weighted average basic NIQ ordinary shares outstanding (in shares)	295,044,637	245,000,000
Weighted average diluted NIQ ordinary shares outstanding (in shares)	295,044,637	245,000,000