CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Millions	Reliance Shareholders'	Common Stock and Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Non-controlling Interests	Total
Balance at Dec. 31, 2020		$ 0.1	$ 5,193.2	$ (77.9)	$ 7.3	$ 5,122.7
Increase (Decrease) in Stockholders' Equity
Net income attributable to Reliance			991.7			995.1
Cash dividends and dividend equivalents			(132.3)
Other comprehensive (loss) income				(5.0)	3.4	(5.0)
Dividends paid					(3.5)
Stock-based compensation		55.1
Common stock withheld related to net share settlements		(9.2)
Repurchase of common shares		(45.9)	(109.1)			(155.0)
Balance at Sep. 30, 2021	$ 5,860.7	0.1	5,943.5	(82.9)	7.2	5,867.9
Balance at Jun. 30, 2021		5.7	5,700.6	(74.6)	7.3	5,639.0
Increase (Decrease) in Stockholders' Equity
Net income attributable to Reliance			395.7			396.7
Cash dividends and dividend equivalents			(43.7)
Other comprehensive (loss) income				(8.3)	1.0	(8.3)
Dividends paid					(1.1)
Stock-based compensation		17.2
Common stock withheld related to net share settlements		(0.9)
Repurchase of common shares		(21.9)	(109.1)			(131.0)
Balance at Sep. 30, 2021	5,860.7	0.1	5,943.5	(82.9)	7.2	5,867.9
Balance at Dec. 31, 2021		0.1	6,155.3	(68.9)	7.2	6,093.7
Increase (Decrease) in Stockholders' Equity
Net income attributable to Reliance			1,489.6			1,492.9
Cash dividends and dividend equivalents			(163.5)
Other comprehensive (loss) income				(45.0)	3.3	(45.0)
Capital contributions					0.3
Dividends paid					(2.0)
Stock-based compensation		48.4
Common stock withheld related to net share settlements		(21.6)
Repurchase of common shares		(26.8)	(520.9)			(547.7)
Balance at Sep. 30, 2022	6,846.7	0.1	6,960.5	(113.9)	8.8	6,855.5
Balance at Jun. 30, 2022		0.1	6,942.5	(88.3)	8.8	6,863.1
Increase (Decrease) in Stockholders' Equity
Net income attributable to Reliance			393.5			394.4
Cash dividends and dividend equivalents			(52.9)
Other comprehensive (loss) income				(25.6)	0.9	(25.6)
Dividends paid					(0.9)
Stock-based compensation		18.6
Common stock withheld related to net share settlements		(4.5)
Repurchase of common shares		(14.1)	(322.6)			(336.7)
Balance at Sep. 30, 2022	$ 6,846.7	$ 0.1	$ 6,960.5	$ (113.9)	$ 8.8	$ 6,855.5