Stockholders' Equity Common Stock (Details)	12 Months Ended
	Dec. 29, 2012		Dec. 31, 2011		Dec. 25, 2010
Common stock issued, Class A
Capital Stock Activity [Roll Forward]
Common stock issued, beginning balance (in shares)	2,600,000		2,600,000		2,600,000
Shares issued under equity compensation plans	0		0		0
Shares exchanged for common stock					0
Shares exchanged for Class B exchangeable shares			0
Common stock issued, ending balance (in shares)	2,600,000		2,600,000		2,600,000
Common stock issued, Class B
Capital Stock Activity [Roll Forward]
Common stock issued, beginning balance (in shares)	162,700,000	[1]	162,000,000	[1]	159,400,000	[1]
Shares issued under equity compensation plans	1,500,000	[1]	700,000	[1]	1,400,000	[1]
Shares exchanged for common stock					1,200,000	[1]
Shares exchanged for Class B exchangeable shares			0	[1]
Common stock issued, ending balance (in shares)	164,200,000	[1]	162,700,000	[1]	162,000,000	[1]
Exchangeable shares issued, Class A
Capital Stock Activity [Roll Forward]
Exchangeable stock issued, beginning balance (in shares)	2,900,000		3,000,000		3,200,000
Shares issued under equity compensation plans	0		0		0
Shares exchanged for common stock					(200,000)
Shares exchanged for Class B exchangeable shares			(100,000)
Exchangeable stock issued, ending balance (in shares)	2,900,000		2,900,000		3,000,000
Exchangeable shares issued, Class B
Capital Stock Activity [Roll Forward]
Exchangeable stock issued, beginning balance (in shares)	19,300,000		19,200,000		20,200,000
Shares issued under equity compensation plans	0		0		0
Shares exchanged for common stock					(1,000,000)
Shares exchanged for Class B exchangeable shares			100,000
Exchangeable stock issued, ending balance (in shares)	19,300,000		19,300,000		19,200,000

[1] During 2011, we repurchased Class B common shares which results in a lower number of outstanding shares compared to issued shares. See "Share Repurchase Program" below for further discussion. For all other classes, issued shares equal outstanding shares.