Fair Value Measurements Fair Value Disclosure, Additional Information (Details)	12 Months Ended																									12 Months Ended
	Sep. 30, 2014 USD ($) Swap	Sep. 30, 2013 USD ($) Swap	Sep. 30, 2014 4.875 % Due in 2013	Mar. 31, 2014 1.75 % Due in 2014	Sep. 30, 2013 1.75 % Due in 2014	Sep. 30, 2014 7.7 % Due in 2015	Sep. 30, 2013 7.7 % Due in 2015	Sep. 30, 2014 5.5 % Due in 2016	Sep. 30, 2013 5.5 % Due in 2016	Sep. 30, 2014 2.6 % Due in 2017	Sep. 30, 2013 2.6 % Due in 2017	Sep. 30, 2014 1.4% Due in 2018	Jun. 30, 2014 1.4% Due in 2018	Sep. 30, 2014 7.125 % Due in 2017	Sep. 30, 2013 7.125 % Due in 2017	Mar. 31, 2011 Interest rate swaps 4.875 % Due in 2013 USD ($) Swap	Mar. 31, 2011 Interest rate swaps 1.75 % Due in 2014 USD ($) Swap	Sep. 30, 2013 Interest rate swaps 7.7 % Due in 2015 USD ($) Swap	Sep. 30, 2013 Interest rate swaps 5.5 % Due in 2016 USD ($) Swap	Jun. 30, 2014 Interest rate swaps 2.6 % Due in 2017 USD ($) Swap	Jun. 30, 2014 Interest rate swaps 1.4% Due in 2018 USD ($) Swap	Jun. 30, 2014 Interest rate swaps 7.125 % Due in 2017 USD ($) Swap	Mar. 31, 2011 Interest rate swaps 5.8% Due in 2013 USD ($) Swap	Sep. 30, 2014 Cross Currency Interest Rate Contract [Member] JPY (¥) Swap	Sep. 30, 2013 Cross Currency Interest Rate Contract [Member] JPY (¥) Swap	Sep. 30, 2014 Selling, general and administrative USD ($)	Sep. 30, 2014 Unrealized Gains [Member] USD ($)	Sep. 30, 2013 Unrealized Gains [Member] USD ($)	Sep. 30, 2014 Unrealized Losses [Member] USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Amount of Hedged Item																$ 300,000,000	$ 450,000,000	$ 125,000,000	$ 800,000,000	$ 400,000,000	$ 300,000,000	$ 150,000,000	$ 100,000,000
Debt Instrument, Interest Rate, Stated Percentage			4.875%	1.75%	1.75%	7.70%	7.70%	5.50%	5.50%	2.60%	2.60%	1.40%	1.40%	7.125%	7.125%	4.875%	1.75%	7.70%	5.50%	2.60%	1.40%	7.125%	5.80%
Number of fixed to floating interest rate swaps outstanding	13	10														2	5	1	4	4	3	1	1	4	5
Derivative, Notional Amount																								20,000,000,000	25,000,000,000
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax																											0	7,000,000	0
Proceeds from Sale of Available-for-sale Securities, Equity	25,000,000
Available-for-sale Securities, Gross Realized Gains																										8,000,000
Debt Instrument, Fair Value Disclosure	$ 6,800,000,000	$ 5,700,000,000