Debt (Narrative) (Details) (USD $)	9 Months Ended				1 Months Ended			1 Months Ended		1 Months Ended								1 Months Ended		9 Months Ended
	Jun. 30, 2012	Jul. 02, 2011	Oct. 01, 2011	Sep. 27, 2008 2016 Notes [Member]	Jun. 30, 2012 4.50% Senior Notes Due June 2022 (2022 Notes) [Member]	Jun. 30, 2012 3.25% Convertible Senior Unsecured Notes Due October 15, 2013 [Member]	Sep. 30, 2008 3.25% Convertible Senior Unsecured Notes Due October 15, 2013 [Member]	Jun. 30, 2012 10.50% Senior Notes Due March 2014 (2014 Notes) [Member]	Jun. 30, 2012 GO Zone Tax-Exempt Bonds Due October 2033 [Member]	Nov. 30, 2008 Go Zone Tax Exempt Bonds [Member]	Oct. 31, 2008 Go Zone Tax Exempt Bonds [Member]	Jun. 30, 2012 Prior To Credit Rating Adjustment [Member] 2016 Notes [Member]	Jul. 02, 2011 Prior To Credit Rating Adjustment [Member] 2016 Notes [Member]	Jun. 30, 2012 After Credit Rating Adjustment [Member] 2016 Notes [Member]	Jul. 02, 2011 After Credit Rating Adjustment [Member] 2016 Notes [Member]	Jun. 30, 2012 Standby Letters of Credit [Member]	Jun. 30, 2012 Bilateral Letters Of Credit [Member]	Sep. 30, 2008 Accounting Standards Update 2010-11 [Member] 3.25% Convertible Senior Unsecured Notes Due October 15, 2013 [Member]	Sep. 30, 2008 Common Class A [Member] 3.25% Convertible Senior Unsecured Notes Due October 15, 2013 [Member]	Jun. 30, 2012 Common Class A [Member] 3.25% Convertible Senior Unsecured Notes Due October 15, 2013 [Member]
Debt Instrument [Line Items]
Amount available under credit facility	$ 1,000,000,000
Amount available for borrowing under credit facility	961,000,000
Letters of credit issued amount																39,000,000	150,000,000
Debt instrument, face amount					1,000,000,000		458,000,000
Interest rate				6.60%	4.50%	3.25%	3.25%	10.50%
Debt Instrument, Unamortized Discount	33,000,000		76,000,000		5,000,000
Issue price percent of face value					99.458%
Proceeds from Issuance of Unsecured Debt					995,000,000
Payments of Debt Issuance Costs					9,000,000
Interest rate at period end									0.18%			6.85%	7.35%	6.60%	6.85%
Conversion rate																			59.1935
Principal amounts for conversion							1,000													1,000
Conversion price, per share																			$ 16.89
Debt Instrument, Convertible, Subordinated Exchangeable Threshold Period, During Trading Period Evaluation																				20 days
Debt Instrument, Convertible, Subordinated Exchangeable Trading Period Evaluation in Preceding Quarter																				30 days
Minimum percentage of exchange price																				130.00%
Minimum trade price																				$ 21.96
Debt Instrument, Convertible, Trading Period																				5 days
Debt Instrument, Convertible, Subordinated Exchangeable Measurement Period																				10 days
Percentage trading price per principal amount, upper limit																				98.00%
Debt instrument, interest rate, effective percentage																		8.26%
Discount on note recognized from adoption of accounting standard																		92,000,000
After tax amount recorded to capital in excess of par value																		56,000,000
Discount Accretion Term																		5 years
Deferred tax assets																			36,000,000
Call options purchased in private transactions																			94,000,000
Number of class A stock that can be acquired through call options																			27,000,000
Option Indexed to Issuer's Equity, Strike Price																			16.89
Proceeds from sale of warrants																			44,000,000
Shares able to be purchased through warrants																			27,000,000
Exercise price of warrants, per share																			22.31
Maximum amount of shares that may be issued to satisfy conversion																			35,900,000
Increase in stock price that would result in the issuance of additional stock																			10.00%
Conversion price factoring convertible note hedge and warrant transactions, per share																			$ 22.31
Additional stock issuance if increase in share price																			2,500,000
Extinguishment of Debt, Amount								790,000,000
Loss on Extinguishment of Debt	167,000,000	0						167,000,000
Proceeds from the sale of Gulf Opportunity Zone tax-exempt bonds											$ 100,000,000
Interest rate swap period in force										5 years