Asset-Backed Financing (Schedule Of Secured Notes With Related Maturity) (Details) (Variable Interest Entity, Primary Beneficiary [Member], Secured Debt [Member], USD $)	Dec. 31, 2014
Secured Notes Issued April 2014 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 850,000,000
Weighted average interest rate at date of issuance	0.66%
May 2014 - December 2020 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	650,000,000
Weighted average interest rate at date of issuance	0.57%
August 2013 - June 2018 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	675,306,000
Weighted average interest rate at date of issuance	0.59%
November 2012 - February 2018 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	513,300,000
Weighted average interest rate at date of issuance	0.88%
September 2012 - August 2017 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	573,380,000
Weighted average interest rate at date of issuance	0.76%
December 2011 - April 2018 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 600,000,000
Weighted average interest rate at date of issuance	1.05%