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			596.0			598.4
Cash dividends and dividend equivalents			(88.6)
Other comprehensive (loss) income				3.3	2.4	3.3
Dividend paid					(2.4)
Stock-based compensation		37.9
Common stock withheld related to net share settlements		(8.3)
Repurchase of common shares		(24.0)				(24.0)
Balance at Jun. 30, 2021	$ 5,631.7	5.7	5,700.6	(74.6)	7.3	5,639.0
Balance at Mar. 31, 2021		6.6	5,415.3	(79.1)	6.2	5,349.0
Increase (Decrease) in Stockholders' Equity
Net income			329.1			330.2
Cash dividends and dividend equivalents			(43.8)
Other comprehensive (loss) income				4.5	1.1	4.5
Stock-based compensation		23.2
Common stock withheld related to net share settlements		(0.1)
Repurchase of common shares		(24.0)				(24.0)
Balance at Jun. 30, 2021	5,631.7	5.7	5,700.6	(74.6)	7.3	5,639.0
Balance at Dec. 31, 2021		0.1	6,155.3	(68.9)	7.2	6,093.7
Increase (Decrease) in Stockholders' Equity
Repurchase of common shares						(17.1)
Balance at Mar. 31, 2022		0.1	6,599.5	(68.3)	7.4	6,538.7
Balance at Dec. 31, 2021		0.1	6,155.3	(68.9)	7.2	6,093.7
Increase (Decrease) in Stockholders' Equity
Net income			1,096.1			1,098.5
Cash dividends and dividend equivalents			(110.6)
Other comprehensive (loss) income				(19.4)	2.4	(19.4)
Capital contributions					0.3
Dividend paid					(1.1)
Stock-based compensation		29.8
Common stock withheld related to net share settlements		(17.1)
Repurchase of common shares		(12.7)	(198.3)			(211.0)
Balance at Jun. 30, 2022	6,854.3	0.1	6,942.5	(88.3)	8.8	6,863.1
Balance at Mar. 31, 2022		0.1	6,599.5	(68.3)	7.4	6,538.7
Increase (Decrease) in Stockholders' Equity
Net income			572.8			573.9
Cash dividends and dividend equivalents			(53.9)
Other comprehensive (loss) income				(20.0)	1.1	(20.0)
Capital contributions					0.3
Stock-based compensation		18.0
Repurchase of common shares		(18.0)	(175.9)			(193.9)
Balance at Jun. 30, 2022	$ 6,854.3	$ 0.1	$ 6,942.5	$ (88.3)	$ 8.8	$ 6,863.1