Statements of Cash Flows - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017
Operating Activities
Net income		$ 44.7	$ 37.5
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization		56.3	52.1
Deferred income taxes		4.3	58.0
Other adjustments for non-cash items		0.5	0.7
Changes in operating assets and liabilities		117.9	11.9
Net cash provided by operating activities		223.7	160.2
Investing Activities
Property, plant and equipment purchased		(171.8)	(135.2)
Other		(3.9)	(3.7)
Net cash used in investing activities		(175.7)	(138.9)
Financing Activities
Issuance (repayment) of short-term debt, net		(55.0)	25.0
Issuance of long-term debt		150.0
Repayment of long-term debt		(120.0)
Repayment of affiliated current borrowings, net		(26.6)	(48.0)
Other		(1.4)
Net cash used in financing activities		(53.0)	(23.0)
Decrease in cash and equivalents		(5.0)	(1.7)
Cash, restricted cash and equivalents at beginning of period	[1]	6.7	7.6
Cash, restricted cash and equivalents at end of period	[1]	1.7	5.9
Significant noncash investing activities:
Accrued capital expenditures		$ 10.0	$ 21.3

[1] No amounts were held in restricted cash and equivalents in any of the periods presented