Preferred Stock (Narrative) (Details) - Preferred Stock - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 26, 2015	Dec. 27, 2014
Preferred Stock [Line Items]
Preferred stock, authorized (in shares)	3,000,000	3,000,000
Preferred stock, dividends per share	$ 5.46
Preferred Stock, Shares Issued	803,953	803,953	800,000
Outstanding preferred shares, fair value	$ 64	$ 67
Preferred stock convertible at the option of the holder	4.9625
Preferred stock call price	$ 78
Preferred shares, outstanding	122,553	135,053