Short-Term Debt (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Short term borrowings
Commercial Paper	$ 5,130	[1]	$ 2,783	[1]
Notes payable to banks and others with originating terms of one year or less	49		23
Current maturities of long-term debt	0		20
Current maturities of long-term capital leases	34		38
Redeemable long term obligations - Long-term debt	3,152		3,151
Redeemable long term obligations - Capital leases	9		12
Subtotal	8,374		6,027
Reclassified to long-term debt	(8,000)		(5,900)
Total short-term debt	$ 374		$ 127

[1] Weighted-average interest rates at December 31, 2013 and 2012, were 0.09 percent and 0.13 percent, respectively.