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, 2019	Mar. 31, 2018
Operating activities:
Net cash provided by (used for) operating activities	$ 665.0	$ 473.7
Investing activities:
Capital expenditures	(625.4)	(426.7)
Cash paid related to business combinations, net of cash acquired	(3,349.3)	(185.2)
Cash receipts on sold trade receivables		253.1
Investment in unconsolidated entities	(0.2)	(111.0)
Proceeds from sale of property, plant and equipment	105.3	15.7
Proceeds from property, plant and equipment insurance settlement	8.8	4.8
Other	10.2	8.2
Net cash used for investing activities	(3,850.6)	(441.1)
Financing activities:
Proceeds from issuance of notes	1,498.5	1,197.3
(Repayments) additions to revolving credit facilities	172.0	94.3
Additions to debt	3,957.9	853.2
Repayments of debt	(3,209.6)	(2,010.4)
Changes in commercial paper, net	588.3	63.3
Other financing additions (repayments), net	16.6	(24.5)
Issuances of common stock, net of related minimum tax withholdings	3.2	17.4
Purchases of common stock	(88.6)
Cash dividends paid to stockholders	(233.7)	(219.4)
Cash distributions paid to noncontrolling interests	(2.8)	(8.6)
Other	3.0	(24.9)
Net cash provided by (used for) financing activities	2,704.8	(62.3)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(1.8)	(1.9)
Decrease in cash, cash equivalents and restricted cash	(482.6)	(31.6)
Cash, cash equivalents and restricted cash at beginning of period	636.8	304.0
Cash, cash equivalents and restricted cash at end of period	154.2	272.4
Parent [Member]
Operating activities:
Net cash provided by (used for) operating activities	319.1	4.0
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	3.2
Purchases of common stock	(88.6)
Cash dividends paid to stockholders	(233.7)
Intercompany capital receipt	563.0
Other		(4.0)
Net cash provided by (used for) financing activities	243.9	(4.0)
Issuer [Member]
Operating activities:
Net cash provided by (used for) operating activities	(93.4)	(488.3)
Investing activities:
Intercompany notes proceeds	9.2
Intercompany capital investment	(563.0)	(755.3)
Intercompany return of capital		1,356.3
Net cash used for investing activities	(553.8)	601.0
Financing activities:
Proceeds from issuance of notes	1,498.5	1,197.3
(Repayments) additions to revolving credit facilities	67.5	(59.8)
Additions to debt	3,801.9	2.7
Repayments of debt	(1,489.7)	(1,025.2)
Changes in commercial paper, net	588.3	63.3
Issuances of common stock, net of related minimum tax withholdings		17.4
Cash dividends paid to stockholders		(219.4)
Intercompany notes payments	(3,800.0)	(69.0)
Other	(19.5)	(20.0)
Net cash provided by (used for) financing activities	647.0	(112.7)
Decrease in cash, cash equivalents and restricted cash	(0.2)
Cash, cash equivalents and restricted cash at beginning of period	0.2
Cash, cash equivalents and restricted cash at end of period	0.0
Guarantor Subsidiaries [Member]
Operating activities:
Net cash provided by (used for) operating activities	(196.9)	(268.8)
Investing activities:
Capital expenditures	(2.4)	(0.4)
Intercompany notes issued		(1.4)
Intercompany notes proceeds	1.3	3.2
Intercompany capital investment		(300.8)
Intercompany return of capital		821.0
Other	8.6	6.6
Net cash used for investing activities	7.5	528.2
Financing activities:
Repayments of debt	(357.5)	(14.8)
Other financing additions (repayments), net		(5.9)
Intercompany notes borrowing	75.7	375.9
Intercompany notes payments		(14.0)
Intercompany capital receipt		736.9
Intercompany capital distribution		(1,356.3)
Net cash provided by (used for) financing activities	(281.8)	(278.2)
Effect of exchange rate changes on cash, cash equivalents and restricted cash		(0.1)
Decrease in cash, cash equivalents and restricted cash	(471.2)	(18.9)
Cash, cash equivalents and restricted cash at beginning of period	490.8	43.3
Cash, cash equivalents and restricted cash at end of period	19.6	24.4
Non-Guarantor Subsidiaries [Member]
Operating activities:
Net cash provided by (used for) operating activities	1,208.6	1,541.0
Investing activities:
Capital expenditures	(623.0)	(426.3)
Cash paid related to business combinations, net of cash acquired	(3,349.3)	(185.2)
Cash receipts on sold trade receivables		253.1
Investment in unconsolidated entities	(0.2)	(111.0)
Proceeds from sale of property, plant and equipment	105.3	15.7
Proceeds from property, plant and equipment insurance settlement	8.8	4.8
Intercompany notes issued	(75.7)	(375.9)
Intercompany notes proceeds	3,800.0	83.0
Other	1.6	1.6
Net cash used for investing activities	(132.5)	(740.2)
Financing activities:
(Repayments) additions to revolving credit facilities	104.5	154.1
Additions to debt	156.0	850.5
Repayments of debt	(1,362.4)	(970.4)
Other financing additions (repayments), net	16.6	(18.6)
Cash distributions paid to noncontrolling interests	(2.8)	(8.6)
Intercompany notes borrowing		1.4
Intercompany notes payments	(10.5)	(3.2)
Intercompany capital receipt	563.0	319.2
Intercompany capital distribution		(821.0)
Intercompany dividends	(572.4)	(314.2)
Other	22.5	(0.9)
Net cash provided by (used for) financing activities	(1,085.5)	(811.7)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(1.8)	(1.8)
Decrease in cash, cash equivalents and restricted cash	(11.2)	(12.7)
Cash, cash equivalents and restricted cash at beginning of period	145.8	260.7
Cash, cash equivalents and restricted cash at end of period	134.6	248.0
Eliminations [Member]
Operating activities:
Net cash provided by (used for) operating activities	(572.4)	(314.2)
Investing activities:
Intercompany notes issued	75.7	377.3
Intercompany notes proceeds	(3,810.5)	(86.2)
Intercompany capital investment	1,126.0	1,056.1
Intercompany return of capital		(2,177.3)
Net cash used for investing activities	(2,608.8)	(830.1)
Financing activities:
Intercompany notes borrowing	(75.7)	(377.3)
Intercompany notes payments	3,810.5	86.2
Intercompany capital receipt	(1,126.0)	(1,056.1)
Intercompany capital distribution		2,177.3
Intercompany dividends	572.4	314.2
Net cash provided by (used for) financing activities	$ 3,181.2	$ 1,144.3