Derivative Financial Instruments (Schedule of Interest Rate Swap Derivatives) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended
	Nov. 30, 2012	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2014
Swap Derivative 1 Point 71 Percent Maturing January 2, 2014 [Member]
Derivative [Line Items]
Notional Value	$ 395	$ 1,100
Effective Date		Jan. 02, 2012
Expiration Date	Jan. 02, 2014	Jan. 02, 2014
Fixed Rate		1.71%
Swap Derivative 1 Point 02 Percent Maturing January 2, 2016 [Member]
Derivative [Line Items]
Notional Value		$ 500	$ 500	$ 500
Effective Date		Jan. 02, 2014		Jan. 02, 2014
Expiration Date		Jan. 02, 2016	Jan. 02, 2016
Fixed Rate		1.02%	1.02%	1.02%