Pension Benefits (Level 3 Gains and Losses) (Details) (USD $) In Millions, unless otherwise specified				12 Months Ended						12 Months Ended				12 Months Ended				12 Months Ended				12 Months Ended
	Dec. 31, 2011 Pension [Member]	Jan. 01, 2011 Pension [Member]	Jan. 02, 2010 Pension [Member]	Dec. 31, 2011 Level 3 [Member]	Jan. 01, 2011 Level 3 [Member]	Dec. 31, 2011 Level 3 [Member] Pension [Member]	Jan. 01, 2011 Level 3 [Member] Pension [Member]	Dec. 31, 2011 Bonds, Corporate [Member] Pension [Member]	Jan. 01, 2011 Bonds, Corporate [Member] Pension [Member]	Dec. 31, 2011 Bonds, Corporate [Member] Level 3 [Member] Pension [Member]	Jan. 01, 2011 Bonds, Corporate [Member] Level 3 [Member] Pension [Member]	Dec. 31, 2011 Bonds, Other [Member] Pension [Member]	Jan. 01, 2011 Bonds, Other [Member] Pension [Member]	Dec. 31, 2011 Bonds, Other [Member] Level 3 [Member] Pension [Member]	Jan. 01, 2011 Bonds, Other [Member] Level 3 [Member] Pension [Member]	Dec. 31, 2011 Real Estate [Member] Pension [Member]	Jan. 01, 2011 Real Estate [Member] Pension [Member]	Dec. 31, 2011 Real Estate [Member] Level 3 [Member] Pension [Member]	Jan. 01, 2011 Real Estate [Member] Level 3 [Member] Pension [Member]	Dec. 31, 2011 Other [Member] Pension [Member]	Jan. 01, 2011 Other [Member] Pension [Member]	Dec. 31, 2011 Other [Member] Level 3 [Member] Pension [Member]	Jan. 01, 2011 Other [Member] Level 3 [Member] Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value beginning of year	$ 3,931	$ 3,967	$ 3,323			$ 66	$ 37	$ 299	$ 351	$ 1	$ 3	$ 55	$ 29	$ 0	$ 4	$ 105	$ 58	$ 58	$ 32	$ 7	$ 2	$ 7	$ (2)
Purchases						53	26			1	0			0	1			50	19			2	6
Sales						(11)	(7)			(1)	(2)			0	(5)			(7)	0			(3)	0
Realized and unrealized gain (loss)						4	8			0	0			0	0			4	7			0	1
Transfer out						0	2			0	0			0	0			0	0			0	2
Fair value end of year	3,931	3,967	3,323			112	66	299	351	1	1	55	29	0	0	105	58	105	58	7	2	6	7
Gain included in net change in Level 3 assets				$ 4	$ 7