Supplemental Information (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended									12 Months Ended
	Jul. 31, 2015	Sep. 30, 2017		Jun. 30, 2017	[1]	Mar. 31, 2017	[1]	Dec. 31, 2016	[1]	Sep. 30, 2015	Sep. 30, 2017		Sep. 30, 2015
Supplemental Information [Abstract]
Gain on land sales		$ 12.2	[1]	$ 0.0		$ 0.0		$ 0.0		$ 33.6	$ 12.2	[1]
Business Acquisition [Line Items]
Payments for repurchase of redeemable noncontrolling interest	$ 277.9												$ 277.9
Indura S.A.
Business Acquisition [Line Items]
Percentage of equity interest purchased	30.50%
Ownership percentage		97.80%									97.80%

[1] The gain is reflected on the consolidated income statements in "Other income (expense), net." For additional information, see Note 23, Supplemental Information.