CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended				9 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Net sales	$ 4,690.0		$ 4,137.5		$ 13,637.4	$ 12,048.5
Cost of goods sold	3,701.1		3,270.4		10,967.1	9,618.5
Selling, general and administrative, excluding intangible amortization	442.4		380.7		1,287.4	1,157.3
Selling, general and administrative intangible amortization	102.4		75.6		297.7	223.3
Loss (gain) on disposal of assets	6.5		2.7		(37.3)	6.6
Multiemployer pension withdrawals	(1.7)		4.2		(1.7)	184.2
Land and Development impairments		$ 13.0	1.7	$ 27.6	13.0	29.3
Restructuring and other costs	17.9		17.1		107.1	65.1
Operating profit (loss)	421.4		385.1		1,004.1	764.2
Interest expense, net	(111.1)		(76.7)		(317.3)	(219.8)
(Loss) gain on extinguishment of debt	(3.2)		0.9		(4.7)
Pension and other postretirement non-service income	18.9		21.3		54.9	70.5
Other income (expense), net	3.7		9.7		(2.3)	13.3
Equity in income of unconsolidated entities	1.7		15.5		8.3	31.2
Income before income taxes	331.4		355.8		743.0	659.4
Income tax (expense) benefit	(77.6)		(84.5)		(187.5)	969.9
Consolidated net income (loss)	253.8		271.3		555.5	1,629.3
Less: Net income attributable to noncontrolling interests	(1.2)		(3.1)		(3.4)	(2.8)
Net income (loss) attributable to common stockholders	$ 252.6		$ 268.2		$ 552.1	$ 1,626.5
Basic earnings per share attributable to common stockholders	$ 0.98		$ 1.05		$ 2.15	$ 6.36
Diluted earnings per share attributable to common stockholders	$ 0.98		$ 1.03		$ 2.13	$ 6.25
Basic weighted average shares outstanding	257.3		256.1		256.2	255.7
Diluted weighted average shares outstanding	258.6		260.6		259.1	260.0
Cash dividends paid per common share	$ 0.455		$ 0.43		$ 1.365	$ 1.29