Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash Flows from Operating Activities:
Net income	$ 141.7	$ 186.8
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion, and amortization of intangibles	100.3	94.8
Amortization of deferred financing costs	0.6	2.2
Share-based compensation expense	10.1	6.9
Deferred income tax provision	13.5	18.8
Pension and post-retirement benefits expense, net of contributions	1.0	7.3
Other, net	5.5	4.2
Increase in assets —
Accounts receivable	(34.0)	(28.4)
Inventories	(15.7)	(36.1)
Prepaid expenses and other current assets	(23.0)	(19.7)
Increase (decrease) in liabilities —
Accounts payable	28.5	13.2
Accrued liabilities	(22.0)	(44.0)
Federal and state income taxes payable / receivable	30.2	30.0
Net cash provided by operating activities	236.7	236.0
Cash Flows from Investing Activities:
Additions to property, plant, and equipment	(70.5)	(78.8)
Additions to other long term assets	(2.7)	(1.3)
Purchases of marketable debt securities, net of redemptions	(3.9)
Proceeds from disposals	0.1
Net cash used for investing activities	(77.0)	(80.1)
Cash Flows from Financing Activities:
Repayments of debt and finance lease obligations	(0.4)	(0.3)
Common stock dividends paid	(74.8)	(74.7)
Net cash used for financing activities	(75.2)	(75.0)
Net increase in cash and cash equivalents	84.5	80.9
Cash and cash equivalents, beginning of period	679.5	361.5
Cash and cash equivalents, end of period	$ 764.0	$ 442.4