Derivative Instruments (Schedule of Fair Value Holding Percentage) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Derivative Instruments, Fair Value [Line Items]
Derivative asset, fair value, net		$ 29.2
Derivative Instrument Holding Percentage	100.00%	100.00%
Credit Suisse [Member]
Derivative Instruments, Fair Value [Line Items]
Derivative Instrument Holding Percentage	46.00%	40.00%
Societe Generale [Member]
Derivative Instruments, Fair Value [Line Items]
Derivative Instrument Holding Percentage	31.00%	22.00%
Bnp Paribas [Member]
Derivative Instruments, Fair Value [Line Items]
Derivative Instrument Holding Percentage	0.00%	33.00%
Bbva Compass [Member]
Derivative Instruments, Fair Value [Line Items]
Derivative Instrument Holding Percentage	0.00%	3.00%
Wells Fargo [Member]
Derivative Instruments, Fair Value [Line Items]
Derivative Instrument Holding Percentage	23.00%	2.00%
Level 2 [Member] | Level 2 [Member]
Derivative Instruments, Fair Value [Line Items]
Derivative asset, fair value, net	$ 9.3