Investments Equity Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 30, 2017
Equity Securities [Line Items]
Equity Securities, FV-NI	$ 2,976,660	$ 2,547,180
Equity Securities [Member]
Equity Securities [Line Items]
Equity Securities, FV-NI	2,815,353	2,383,095
Equity Securities, Restricted [Member]
Equity Securities [Line Items]
Equity Securities, FV-NI, Restricted	$ 161,307	$ 164,085