Derivative Financial Instruments (Schedule of Interest Rate Swap Derivatives) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended				3 Months Ended
	Dec. 31, 2012 Swap Derivative 4 Point 92 Percent Maturing January 2, 2012 [Member]		Dec. 31, 2012 Swap Derivative 4 Point 33 Percent Maturing January 2, 2012 [Member]		Mar. 31, 2013 Swap Derivative 1 Point 71 Percent Maturing January 2, 2014 [Member]		Mar. 31, 2013 Swap Derivative 1 Point 02 Percent Maturing January 2, 2016 [Member]
Derivative [Line Items]
Notional value	$ 1,100		$ 500		$ 1,100		$ 500
Effective date	Jan. 02, 2012		Jan. 02, 2014		Jan. 02, 2012		Jan. 02, 2014
Expiration date	Jan. 02, 2014		Jan. 02, 2016		Jan. 02, 2014		Jan. 02, 2016
Fixed rate	1.71%	[1]	1.02%	[1]	1.71%	[1]	1.02%	[1]

[1] Fixes the LIBOR portion of the Company's US-dollar denominated variable rate borrowings (Note 9).