Stockholders' Equity (Dividends Declared on Common Stock) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 14, 2014	Mar. 22, 2014	Jun. 15, 2013	Mar. 23, 2013	Jun. 14, 2014	Jun. 15, 2013
Dividends Payable [Line Items]
Date Declared	May 14, 2014	Mar. 12, 2014	May 14, 2013	Mar. 14, 2013
Per-Share Amounts	$ 0.23	$ 0.20	$ 0.2	$ 0.175
Total	$ 53.1	$ 46.2	$ 48.2	$ 42.2	$ 99.3	$ 90.4
Dividends Declared On Common Stock
Dividends Payable [Line Items]
Record Date	Jun. 19, 2014	Mar. 24, 2014	Jun. 20, 2013	Mar. 25, 2013