CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
COMPREHENSIVE INCOME:
Net income	$ 1,548.2	$ 732.4	$ 778.8
Other comprehensive income (loss) net of tax:
Decrease (increase) in pension and other post-retirement benefits (net of income tax of $2.1, $(1.6) and $2.6, respectively)	(2.9)	2.6	(3.5)
Foreign currency translation adjustments		0.3
Total other comprehensive income (loss)	(2.9)	2.9	(3.5)
Total comprehensive income	1,545.3	735.3	775.3
Comprehensive income attributable to the non-controlling interest	5.2	3.9	2.3
Comprehensive income attributable to SCC	$ 1,540.1	$ 731.4	$ 773.0