Assets Held-for-Sale, Discontinued Operations, and Dispositions (Narrative) (Details) $ in Millions				1 Months Ended					3 Months Ended								12 Months Ended
	Dec. 21, 2018 USD ($)	Oct. 31, 2018 USD ($)	Jul. 01, 2017 USD ($)	Sep. 30, 2019 USD ($)	May 31, 2019 USD ($)	Sep. 30, 2018 USD ($)	May 31, 2018 USD ($)	Mar. 31, 2018 USD ($) brand	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds received in advance of sale of business																	$ 90.0	$ 0.0	$ 0.0
Total revenues									$ 785.6	$ 750.1	$ 878.4	$ 774.4	$ 798.7	$ 655.0	$ 417.7	$ 392.8	3,188.5	2,264.2	1,713.3
Goodwill, impairment loss																		54.9
Share-based compensation																	22.9	30.4	12.8
Proceeds from disposition of assets, net of cash sold																	349.1	219.2	1.5
Gain on equity method investment														(12.9)
Earnings from continuing operations									(3.6)	$ 28.4	$ 88.1	$ 16.2	16.6	(95.4)	$ 159.4	$ 33.4	129.1	114.0	188.9
Earnings (loss) from continuing operations before income taxes																	140.6	(9.6)	290.3
MXM
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Earnings from continuing operations							$ 11.5
Earnings (loss) from continuing operations before income taxes																		(0.8)	$ 11.2
Outsourcing Agreement | Other
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues																	4.8
Transition Services Agreement | Selling, general and administrative expenses
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues																	$ 18.9
Minimum | Outsourcing Agreement | Selling, general and administrative expenses
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
OA term																	1 year
Maximum | Outsourcing Agreement | Selling, general and administrative expenses
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
OA term																	5 years
Discontinued operations, disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on disposal																	$ 2.1
Discontinued operations, disposed of by sale | Performance guarantee
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Guarantee obligations, current carrying amount									8.0				8.7				8.0	8.7
Discontinued operations, disposed of by sale | Time, Inc.
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds received in advance of sale of business		$ 190.0
Discontinued operations, disposed of by sale | Fortune
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds received in advance of sale of business	$ 150.0
Discontinued operations, disposed of by sale | Time Inc. (UK) Ltd
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of brands | brand								60
Discontinued operations, disposed of by sale | Time Inc. (UK) Ltd | Performance guarantee
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Guarantee obligations, current carrying amount								$ 9.2	8.0					$ 9.2			8.0
Maximum lease guarantee obligation									66.9								66.9
Discontinued operations, held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on disposal																		(12.3)
Share-based compensation																	$ 0.5	3.7
Discontinued operations, held-for-sale | Sports Illustrated
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds received in advance of sale of business					$ 90.0
Goodwill, impairment loss									$ 8.5
Earn-out provision					$ 20.0
Discontinued operations, held-for-sale | Sports Illustrated | Forecast
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Amount owing for accounts receivable and accounts payable				$ 11.6
Working capital true-up				$ 1.2
Disposal group, disposed of by sale, not discontinued operations | Charleston Tennis LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds received in advance of sale of business			$ 0.6
Ownership percentage interest			70.00%
Note receivable from other disposition			$ 8.5
Note receivable from other disposition, installment period			8 years
Note receivable from other disposition, unamortized discount													3.2					3.2
Note receivable from other disposition, allowance													$ 3.0					$ 3.0
Remeasurement gain (loss) on disposition of assets			$ 1.0
Ownership percentage retained			30.00%
Cash received						$ 13.3
Proceeds from disposition of assets, net of cash sold						5.1
Repayment of principal and interest accrued						8.2
Disposal group, disposed of by sale, not discontinued operations | Charleston Tennis LLC | Selling, general and administrative expenses
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net gain on disposition of assets			$ 3.3			10.4
Disposal group, disposed of by sale, not discontinued operations | Charleston Tennis LLC | Nonoperating income (expense)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on equity method investment						$ 4.1