Divestitures (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions				3 Months Ended				6 Months Ended		12 Months Ended
	Jan. 28, 2019	Jan. 02, 2019	Nov. 30, 2017	Mar. 31, 2019	Dec. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2018	Sep. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax benefit				$ (22.7)			$ (1.7)	$ (26.0)	$ (122.2)
FGL Merger [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Reclassification of accumulated other comprehensive income to income from discontinued operations										$ 445.9
Income tax benefit						$ 5.9
Global Battery And Lighting [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale		$ 996.3
Depreciation and amortization expense				0.0				0.0	8.3
Transaction costs associated with the divestiture				2.3			16.9	12.9	19.3
Indenmifications, acquisition agreement		49.0
Net settlement payable				229.1				229.1
Global Auto Care [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation and amortization expense							$ 3.9	1.4	$ 7.9
Write-down of assets of business held for sale to fair value less cost to sell								110.8
Transaction costs associated with the divestiture				3.0				8.8
Net settlement receivable				8.4				8.4
Fidelity And Guaranty Life [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Estimate fair value less cost to sell held for sale assets											$ 402.2
Fidelity And Guaranty Life [Member] | FGL Merger [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Share price			$ 31.10
Transaction costs associated with the divestiture			$ 1,488.3
Front Street RE Cayman Ltd [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Estimate fair value less cost to sell held for sale assets											$ 19.0
Home And Personal Care [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation and amortization expense					$ 29.0
Transaction costs associated with the divestiture				$ 0.9				5.5
Energizer [Member] | Global Battery And Lighting [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Purchase price		1,956.2
Contingent settlement		200.0
Purchase price adjustment		$ 200.0
Energizer [Member] | Global Battery And Lighting [Member] | Maximum [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Potential downward adjustment, percentage		75.00%
Potential upward adjustment, percentage		25.00%
Energizer [Member] | Global Battery And Lighting [Member] | Downward Adjustment Equal To 75% [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Purchase price adjustment		$ 600.0
Energizer [Member] | Global Battery And Lighting [Member] | Upward Adjustment Equal To 25% [Member] | Maximum [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Purchase price adjustment		$ 200.0
Energizer [Member] | Global Auto Care [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Purchase price, cash	$ 938.7
Write-down of assets of business held for sale to fair value less cost to sell								$ 110.8
Energizer [Member] | Global Auto Care [Member] | Common Stock [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Stock consideration, value	$ 242.1
CF Entities [Member] | Front Street RE Cayman Ltd [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Transaction costs associated with the divestiture			65.0
Amount of purchase price deposited in escrow			$ 6.5