Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Earnings Per Share [Abstract]
Net income available to IPG common stockholders	$ 159.4	$ 91.7
Weighted-average number of common shares outstanding, Basic	394.5	391.5
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	3.9	4.5
Weighted-average number of common shares outstanding, Diluted	398.4	396.0
Earnings per share, Basic	$ 0.40	$ 0.23
Earnings per share, Diluted	$ 0.40	$ 0.23