Selected Condensed Consolidating Financial Statements of Parent, Issuer, Guarantors and Non-Guarantors - Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating activities:
Net cash provided by (used for) operating activities	$ 598.8	$ 665.0
Investing activities:
Capital expenditures	(616.2)	(625.4)
Cash paid related to business combinations, net of cash acquired		(3,349.3)
Investment in unconsolidated entities	(0.7)	(0.2)
Proceeds from sale of property, plant and equipment	21.3	105.3
Proceeds from property, plant and equipment insurance settlement	1.4	8.8
Other, net	4.9	10.2
Net cash used for investing activities	(589.3)	(3,850.6)
Financing activities:
Proceeds from issuance of notes		1,498.5
Additions to revolving credit facilities	375.0	192.2
Repayments of revolving credit facilities	(65.0)	(20.0)
Additions to debt	580.1	3,957.9
Repayments of debt	(208.2)	(3,209.6)
(Repayments) additions to commercial paper, net	(34.8)	588.3
Other debt additions, net	85.9	16.4
Issuances of common stock, net of related minimum tax withholdings	13.4	3.2
Purchases of common stock		(88.6)
Cash dividends paid to stockholders	(240.7)	(233.7)
Cash distributions paid to noncontrolling interests	(0.7)	(2.8)
Other, net	2.1	3.0
Net cash provided by financing activities	507.1	2,704.8
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(28.0)	(1.8)
Increase (decrease) in cash, cash equivalents and restricted cash	488.6	(482.6)
Cash, cash equivalents and restricted cash at beginning of period	151.6	636.8
Cash, cash equivalents and restricted cash at end of period	640.2	154.2
Parent [Member]
Operating activities:
Net cash provided by (used for) operating activities	227.3	319.1
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	13.4	3.2
Purchases of common stock		(88.6)
Cash dividends paid to stockholders	(240.7)	(233.7)
Intercompany capital receipt		563.0
Net cash provided by financing activities	(227.3)	243.9
Issuer [Member]
Operating activities:
Net cash provided by (used for) operating activities	(194.0)	(93.1)
Investing activities:
Intercompany notes proceeds		9.2
Intercompany capital investment		(563.0)
Net cash used for investing activities		(553.8)
Financing activities:
Proceeds from issuance of notes		1,498.5
Additions to revolving credit facilities	350.0	67.2
Additions to debt		3,801.9
Repayments of debt	(200.0)	(1,489.7)
(Repayments) additions to commercial paper, net	(34.8)	588.3
Other debt additions, net	79.0
Intercompany notes payments		(3,800.0)
Other, net		(19.5)
Net cash provided by financing activities	194.2	646.7
Increase (decrease) in cash, cash equivalents and restricted cash	0.2	(0.2)
Cash, cash equivalents and restricted cash at beginning of period		0.2
Cash, cash equivalents and restricted cash at end of period	0.2
Guarantor Subsidiaries [Member]
Operating activities:
Net cash provided by (used for) operating activities	443.7	(196.9)
Investing activities:
Capital expenditures		(2.4)
Proceeds from sale of property, plant and equipment	0.1
Intercompany notes proceeds	3.1	1.3
Other, net	4.9	8.6
Net cash used for investing activities	8.1	7.5
Financing activities:
Repayments of debt		(357.5)
Intercompany notes borrowing		75.7
Net cash provided by financing activities		(281.8)
Increase (decrease) in cash, cash equivalents and restricted cash	451.8	(471.2)
Cash, cash equivalents and restricted cash at beginning of period	17.8	490.8
Cash, cash equivalents and restricted cash at end of period	469.6	19.6
Non-Guarantor Subsidiaries [Member]
Operating activities:
Net cash provided by (used for) operating activities	121.8	635.9
Investing activities:
Capital expenditures	(616.2)	(623.0)
Cash paid related to business combinations, net of cash acquired		(3,349.3)
Investment in unconsolidated entities	(0.7)	(0.2)
Proceeds from sale of property, plant and equipment	21.2	105.3
Proceeds from property, plant and equipment insurance settlement	1.4	8.8
Intercompany notes issued		(75.7)
Intercompany notes proceeds		3,800.0
Other, net		1.6
Net cash used for investing activities	(594.3)	(132.5)
Financing activities:
Additions to revolving credit facilities	25.0	125.0
Repayments of revolving credit facilities	(65.0)	(20.0)
Additions to debt	580.1	156.0
Repayments of debt	(8.2)	(1,362.4)
Other debt additions, net	6.9	16.4
Cash distributions paid to noncontrolling interests	(0.7)	(2.8)
Intercompany notes payments	(3.1)	(10.5)
Intercompany capital receipt		563.0
Other, net	2.1	22.5
Net cash provided by financing activities	537.1	(512.8)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(28.0)	(1.8)
Increase (decrease) in cash, cash equivalents and restricted cash	36.6	(11.2)
Cash, cash equivalents and restricted cash at beginning of period	133.8	145.8
Cash, cash equivalents and restricted cash at end of period	170.4	134.6
Eliminations [Member]
Investing activities:
Intercompany notes issued		75.7
Intercompany notes proceeds	(3.1)	(3,810.5)
Intercompany capital investment		1,126.0
Net cash used for investing activities	(3.1)	(2,608.8)
Financing activities:
Intercompany notes borrowing		(75.7)
Intercompany notes payments	3.1	3,810.5
Intercompany capital receipt		(1,126.0)
Net cash provided by financing activities	$ 3.1	$ 2,608.8