SEGMENT INFORMATION - Net Sales, Profit (Loss), and Assets by Segment (Details) $ in Millions	3 Months Ended	9 Months Ended
Jul. 03, 2021 USD ($)	Jun. 27, 2020 USD ($)	Jul. 03, 2021 USD ($) segment	Jun. 27, 2020 USD ($)
Segment Reporting [Abstract]
Number of reportable segments \| segment			3
Segment Reporting Information [Line Items]
Net sales	$ 1,609.7	$ 1,492.7	$ 4,187.2	$ 3,241.3
Impairment, restructuring and other	(0.5)	(4.2)	(3.7)	(2.0)
Equity in income of unconsolidated affiliates	21.5	0.0	20.0	0.0
Interest expense	(21.9)	(20.3)	(57.3)	(63.0)
Other non-operating income, net	1.2	1.9	17.3	7.3
Continuing Operations
Segment Reporting Information [Line Items]
Segment profit (loss)	302.9	266.1	740.2	504.8
Intangible asset amortization	(7.8)	(7.8)	(23.0)	(23.6)
Impairment, restructuring and other	(1.3)	(15.9)	(25.9)	(17.3)
Equity in income of unconsolidated affiliates	21.5	0.0	20.0	0.0
Costs related to refinancing	0.0	0.0	0.0	(15.1)
Interest expense	(21.9)	(20.3)	(57.3)	(63.0)
Other non-operating income, net	1.2	1.9	17.3	7.3
Continuing Operations \| Operating Segments
Segment Reporting Information [Line Items]
Segment profit (loss)	343.1	366.0	923.7	737.2
Continuing Operations \| Corporate
Segment Reporting Information [Line Items]
Segment profit (loss)	(31.9)	(57.8)	(114.6)	(120.7)
U.S. Consumer
Segment Reporting Information [Line Items]
Goodwill reallocated	15.8
Net sales	1,046.2	1,093.0	2,828.4	2,371.7
U.S. Consumer \| Continuing Operations \| Operating Segments
Segment Reporting Information [Line Items]
Segment profit (loss)	264.4	313.8	745.6	648.2
Hawthorne
Segment Reporting Information [Line Items]
Goodwill reallocated	(15.8)
Net sales	421.9	285.7	1,095.1	685.9
Hawthorne \| Continuing Operations \| Operating Segments
Segment Reporting Information [Line Items]
Segment profit (loss)	51.9	37.8	133.7	74.2
Other
Segment Reporting Information [Line Items]
Net sales	141.6	114.0	263.7	183.7
Other \| Continuing Operations \| Operating Segments
Segment Reporting Information [Line Items]
Segment profit (loss)	$ 26.8	$ 14.4	$ 44.4	$ 14.8

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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