Goodwill and other intangible assets (Details) (USD $) In Thousands, unless otherwise specified	Sep. 28, 2014	Dec. 29, 2013
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill	$ 3,836,940	$ 3,790,472
Customer Relationships [Member]
Goodwill and Intangible Assets Disclosure [Line Items]
Finite-Lived Intangible Assets, Gross	300,443	290,845
Finite-Lived Intangible Assets, Accumulated Amortization	200,128	177,515
Other [Member]
Goodwill and Intangible Assets Disclosure [Line Items]
Finite-Lived Intangible Assets, Gross	242,208	213,790
Finite-Lived Intangible Assets, Accumulated Amortization	46,998	23,663
Television station FCC licenses [Member]
Goodwill and Intangible Assets Disclosure [Line Items]
Indefinite-Lived Intangible Assets (Excluding Goodwill)	1,195,093	1,091,204
Intangible Assets Accumulated Amortization	0	0
Mastheads and trade names [Member]
Goodwill and Intangible Assets Disclosure [Line Items]
Indefinite-Lived Intangible Assets (Excluding Goodwill)	82,427	82,570
Intangible Assets Accumulated Amortization	0	0
Goodwill [Member]
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill	3,836,940	3,790,472
Goodwill and Intangible Assets Disclosure [Line Items]
Intangible Assets Accumulated Amortization	$ 0	$ 0