Acquisitions (Summary of Acquired Intangible Assets by Acquisition) (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 31, 2018	Jun. 30, 2017
Time, Inc.
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets subject to amortization	$ 506.8
Intangible assets not subject to amortization	1,146.8
Intangible assets	1,146.8
Time, Inc. | Advertiser relationships
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets subject to amortization	$ 223.5
Useful life of acquired intangible assets	3 years
Time, Inc. | Publisher relationships
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets subject to amortization	$ 125.0
Useful life of acquired intangible assets	7 years
Time, Inc. | Partner relationships
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets subject to amortization	$ 95.0
Useful life of acquired intangible assets	6 years
Time, Inc. | Customer relationships
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets subject to amortization	$ 63.3
Useful life of acquired intangible assets	2 years
Time, Inc. | Trademarks
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets not subject to amortization	$ 640.0
Peachtree TV and FY 2017 Acquisition
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets subject to amortization		$ 16.0
Intangible assets		66.4
Peachtree TV and FY 2017 Acquisition | Retransmission agreements
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets subject to amortization		6.7
Peachtree TV and FY 2017 Acquisition | Customer list
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets subject to amortization		4.2
Peachtree TV and FY 2017 Acquisition | Other
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets subject to amortization		5.1
Peachtree TV and FY 2017 Acquisition | FCC licenses
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets not subject to amortization		$ 50.4
National Media Acquisition | Customer list
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Useful life of acquired intangible assets		10 years
National Media Acquisition | Other
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Useful life of acquired intangible assets		5 years
National Media Acquisition | FY 2017 Acquisition
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets subject to amortization		$ 8.6
Intangible assets		8.6
National Media Acquisition | FY 2017 Acquisition | Retransmission agreements
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets subject to amortization		0.0
National Media Acquisition | FY 2017 Acquisition | Customer list
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets subject to amortization		4.2
National Media Acquisition | FY 2017 Acquisition | Other
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets subject to amortization		4.4
National Media Acquisition | FY 2017 Acquisition | FCC licenses
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets not subject to amortization		$ 0.0
Local Media Acquisition | Retransmission agreements
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Useful life of acquired intangible assets		10 years
Local Media Acquisition | Other
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Useful life of acquired intangible assets		4 years
Local Media Acquisition | Peachtree TV
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets subject to amortization		$ 7.4
Intangible assets		57.8
Local Media Acquisition | Peachtree TV | Retransmission agreements
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets subject to amortization		6.7
Local Media Acquisition | Peachtree TV | Customer list
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets subject to amortization		0.0
Local Media Acquisition | Peachtree TV | Other
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets subject to amortization		0.7
Local Media Acquisition | Peachtree TV | FCC licenses
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets not subject to amortization		$ 50.4