Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Earnings Per Share [Abstract]
Net income available to IPG common stockholders	$ 126.0	$ 159.4
Weighted-average number of common shares outstanding, Basic	385.8	394.5
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	1.6	3.9
Weighted-average number of common shares outstanding, Diluted	387.4	398.4
Earnings per share, Basic	$ 0.33	$ 0.40
Earnings per share, Diluted	$ 0.33	$ 0.40