CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income and comprehensive income	$ 2,434.7	$ 2,648.0	$ 3,411.2
Other comprehensive income (loss) net of tax:
-Decrease (increase) in pension and other post-retirement benefits (net of income tax of $(0.4), $(0.2) and $1.2, respectively)	1.0	1.0	(1.7)
-Derivative instruments classified as cash flow hedge:
- Unrealized (loss) on derivative instruments classified as cash flow hedge (net of income tax of $0.2 million in 2022 and $0.3 million in 2021)		(0.6)	0.6
Total other comprehensive income (loss)	1.0	0.4	(1.1)
Total comprehensive income	2,435.7	2,648.4	3,410.1
Comprehensive income attributable to the non-controlling interest	9.5	9.5	14.1
Comprehensive income attributable to SCC	$ 2,426.2	$ 2,638.9	$ 3,396.0