Long-Term Debt (Debt Redemptions) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	1 Months Ended
	Jun. 30, 2014	Mar. 31, 2014 Mortgages [Member]	Mar. 31, 2014 Securitization Bonds [Member]	Jun. 30, 2014 Tax Exempt Revenue Bonds [Member]	Apr. 30, 2014 Tax Exempt Revenue Bonds [Member]	Jun. 30, 2014 Tax-Exempt Revenue Bonds1 [Member]	Apr. 30, 2014 Tax-Exempt Revenue Bonds1 [Member]
Extinguishment of Debt [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			6.62%	4.875%	2.35%	6.00%	4.65%
Extinguishment of Debt, Amount	$ 281	$ 13	$ 100	$ 36	$ 31	$ 69	$ 32