Fair Value Measurements And Disclosure (Effect Of Derivatives On The Consolidated Statements Of Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Fair Value Hedging Relationships [Member] | Interest expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on long-term debt	$ 21	$ (92)	$ 158	$ (81)
Fair Value Hedging Relationships [Member] | Interest Rate Swaps [Member] | Interest expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on interest rate swaps	(21)	92	(158)	81
Cash Flow Hedging Relationships [Member] | Cross-Currency Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) recognized in accumulated OCI	355	(266)	190	(415)
Cash Flow Hedging Relationships [Member] | Interest Rate Locks [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) recognized in accumulated OCI	0	(105)	0	17
Interest income (expense) reclassified from accumulated OCI into income	(12)	(3)	(32)	(11)
Cash Flow Hedging Relationships [Member] | Foreign Exchange Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) recognized in accumulated OCI	$ 3	$ (13)	$ 3	$ (8)