Long-Term Debt (Details 2) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Extinguishment of Debt [Line Items]
Extinguishment of Debt, Amount	$ 152
Securitization Bonds [Member]
Extinguishment of Debt [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.42%
Extinguishment of Debt, Amount	88
Tax Exempt Revenue Bonds [Member]
Extinguishment of Debt [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.30%
Extinguishment of Debt, Amount	51
Long Term Debt, Other [Member]
Extinguishment of Debt [Line Items]
Extinguishment of Debt, Amount	$ 13