Other Financial Information (Tables)

3 Months Ended

Mar. 31, 2020

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Summary of Changes in Operating Working Capital

	Three Months Ended March 31,
(Millions of dollars)	2020		2019
Accounts receivable	$	37.3	$	(88.5)
Inventories	(16.7)		42.7
Prepaid expenses and other current assets	13.7		(1.1)
Accounts payable and accrued liabilities	(66.1)		48.6
Income taxes payable	6.1		—
Net (increase) decrease in noncash operating working capital	$	(25.7)	$	1.7