Long Term Debt (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2011	Sep. 30, 2011
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Basis for Effective Rate	Variable(5)
Debt Instrument, Face Amount		$ 1,028
Tax Exempt Revenue Bonds [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.35%
Debt Instrument, Face Amount	31
Mortgages2 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.50%
Debt Instrument, Face Amount		140
Mortgages [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.90%	4.31%
Debt Instrument, Face Amount	250	102
Senior Notes1 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	300
Mortages [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.46%
Debt Instrument, Face Amount		77
Mortgages1 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.67%
Debt Instrument, Face Amount		46
Tax-Exempt Revenue Bonds1 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.95%	2.13%
Debt Instrument, Face Amount		$ 82