Selected Condensed Consolidating Financial Statements of Parent, Issuer, Guarantors and Non-Guarantors - Noncash Operating, Investing and Financing Activities (Details) - USD ($) $ in Millions	9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Parent [Member]
Operating activities:
Intercompany receivables	$ (140.9)
Investing activities:
Intercompany capital investment	(10,396.2)
Intercompany return of capital	606.7
Financing activities:
Intercompany capital distribution	(563.0)
Issuer [Member]
Investing activities:
Intercompany capital investment	(5,895.5)	$ (755.3)
Intercompany return of capital	1,479.6	1,356.3
Intercompany notes issued	(3,800.0)
Intercompany notes proceeds	4,519.8
Financing activities:
Intercompany capital receipt	10,396.2
Intercompany capital distribution	(606.7)
Intercompany notes borrowing	4,436.3
Intercompany notes payments		(69.0)
Guarantor Subsidiaries [Member]
Investing activities:
Intercompany capital investment	(6,880.5)	(335.3)
Intercompany return of capital	1,021.4	766.0
Intercompany notes issued	(4,666.4)
Intercompany notes proceeds	4,519.8
Financing activities:
Intercompany capital receipt	5,413.7	736.9
Intercompany capital distribution	(457.5)	(1,356.3)
Intercompany notes borrowing	479.1	392.1
Intercompany notes payments	(959.6)	(14.0)
Intercompany dividends paid	(302.2)
Non-Guarantor Subsidiaries [Member]
Operating activities:
Intercompany payables	140.9
Investing activities:
Intercompany notes issued	(8,715.4)	(392.1)
Intercompany notes proceeds	4,759.6	83.0
Financing activities:
Intercompany capital receipt	7,362.3	353.7
Intercompany capital distribution	(1,480.5)	(766.0)
Intercompany notes borrowing	12,266.4
Intercompany notes payments	(12,839.6)
Intercompany dividends paid	(1,419.6)	(285.9)
Eliminations [Member]
Operating activities:
Intercompany receivables	140.9
Intercompany payables	(140.9)
Investing activities:
Intercompany capital investment	23,172.2	1,090.6
Intercompany return of capital	(3,107.7)	(2,122.3)
Intercompany notes issued	17,181.8	392.1
Intercompany notes proceeds	(13,799.2)	(83.0)
Financing activities:
Intercompany capital receipt	(23,172.2)	(1,090.6)
Intercompany capital distribution	3,107.7	2,122.3
Intercompany notes borrowing	(17,181.8)	(392.1)
Intercompany notes payments	13,799.2	83.0
Intercompany dividends paid	$ 1,721.8	$ 285.9