Selected Condensed Consolidating Financial Statements of Parent, Issuer, Guarantors and Non-Guarantors - Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Operating activities:
Net cash provided by (used for) operating activities	$ 431.2	$ 303.1
Investing activities:
Capital expenditures	(374.8)	(322.0)
Investment in unconsolidated entities	(0.3)
Cash paid related to business combinations, net of cash acquired		(3,342.9)
Proceeds from sale of property, plant and equipment	7.9	88.0
Proceeds from property, plant and equipment insurance settlement	1.4
Other	4.9	4.1
Net cash used for investing activities	(360.9)	(3,572.8)
Financing activities:
Proceeds from issuance of notes		1,498.5
Additions (repayments) to revolving credit facilities	(40.1)	133.6
Additions to debt	101.4	3,806.1
Repayments of debt	(4.0)	(2,847.9)
Changes in commercial paper, net	10.9	447.7
Other financing repayments (additions)	(16.2)	14.6
Issuances of common stock, net of related minimum tax withholdings	15.5	12.9
Purchases of common stock		(44.2)
Cash dividends paid to stockholders	(120.0)	(116.1)
Cash distributions paid to noncontrolling interests	(0.3)	(2.2)
Other	(8.5)	(6.4)
Net cash (used for) provided by financing activities	(61.3)	2,896.6
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(4.2)	(3.0)
Increase (decrease) in cash, cash equivalents and restricted cash	4.8	(376.1)
Cash, cash equivalents and restricted cash at beginning of period	151.6	636.8
Cash, cash equivalents and restricted cash at end of period	156.4	260.7
Parent [Member]
Operating activities:
Net cash provided by (used for) operating activities	104.5	147.4
Investing activities:
Intercompany capital investment		(563.0)
Net cash used for investing activities		(563.0)
Financing activities:
Issuances of common stock, net of related minimum tax withholdings	15.5	12.9
Purchases of common stock		(44.2)
Cash dividends paid to stockholders	(120.0)	(116.1)
Intercompany capital receipt		563.0
Net cash (used for) provided by financing activities	(104.5)	415.6
Issuer [Member]
Operating activities:
Net cash provided by (used for) operating activities	8.3	83.4
Investing activities:
Intercompany notes proceeds		9.3
Intercompany capital investment		(563.0)
Net cash used for investing activities		(553.7)
Financing activities:
Proceeds from issuance of notes		1,498.5
Additions (repayments) to revolving credit facilities	(19.2)	30.7
Additions to debt		3,800.7
Repayments of debt		(1,489.2)
Changes in commercial paper, net	10.9	447.7
Other financing repayments (additions)		0.7
Intercompany notes payments		(3,800.0)
Other		(19.0)
Net cash (used for) provided by financing activities	(8.3)	470.1
Increase (decrease) in cash, cash equivalents and restricted cash		(0.2)
Cash, cash equivalents and restricted cash at beginning of period		0.2
Guarantor Subsidiaries [Member]
Operating activities:
Net cash provided by (used for) operating activities	(17.1)	(519.0)
Investing activities:
Capital expenditures		(1.5)
Proceeds from sale of property, plant and equipment	0.1
Intercompany notes proceeds	3.0	0.6
Other	4.9	3.8
Net cash used for investing activities	8.0	2.9
Financing activities:
Intercompany notes borrowing		75.7
Net cash (used for) provided by financing activities		75.7
Increase (decrease) in cash, cash equivalents and restricted cash	(9.1)	(440.4)
Cash, cash equivalents and restricted cash at beginning of period	17.8	490.8
Cash, cash equivalents and restricted cash at end of period	8.7	50.4
Non-Guarantor Subsidiaries [Member]
Operating activities:
Net cash provided by (used for) operating activities	335.5	591.3
Investing activities:
Capital expenditures	(374.8)	(320.5)
Investment in unconsolidated entities	(0.3)
Cash paid related to business combinations, net of cash acquired		(3,342.9)
Proceeds from sale of property, plant and equipment	7.8	88.0
Proceeds from property, plant and equipment insurance settlement	1.4
Intercompany notes issued		(75.7)
Intercompany notes proceeds		3,800.0
Other		0.3
Net cash used for investing activities	(365.9)	149.2
Financing activities:
Additions (repayments) to revolving credit facilities	(20.9)	102.9
Additions to debt	101.4	5.4
Repayments of debt	(4.0)	(1,358.7)
Other financing repayments (additions)	(16.2)	13.9
Cash distributions paid to noncontrolling interests	(0.3)	(2.2)
Intercompany notes payments	(3.0)	(9.9)
Intercompany capital receipt		563.0
Other	(8.5)	12.6
Net cash (used for) provided by financing activities	48.5	(673.0)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(4.2)	(3.0)
Increase (decrease) in cash, cash equivalents and restricted cash	13.9	64.5
Cash, cash equivalents and restricted cash at beginning of period	133.8	145.8
Cash, cash equivalents and restricted cash at end of period	147.7	210.3
Eliminations [Member]
Investing activities:
Intercompany notes issued		75.7
Intercompany notes proceeds	(3.0)	(3,809.9)
Intercompany capital investment		1,126.0
Net cash used for investing activities	(3.0)	(2,608.2)
Financing activities:
Intercompany notes borrowing		(75.7)
Intercompany notes payments	3.0	3,809.9
Intercompany capital receipt		(1,126.0)
Net cash (used for) provided by financing activities	$ 3.0	$ 2,608.2