Derivatives And Other Financial Instruments (Gains & losses on interest rate contracts qualifying and designated as cash flow hedging instruments) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Reclassified from accumulated other comprehensive loss into interest expense	$ 110	$ 116	$ 222	$ 235