Short-Term Debt (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Short term borrowings
Commercial Paper	[1]	$ 8,252	$ 8,506
Notes payable to banks and others with originating terms of one year or less		20	104
Current maturities of long-term debt		1,487	0
Current maturities of long-term capital leases		17	22
Redeemable long term obligations - Long-term debt		3,152	3,152
Redeemable long term obligations - Capital leases		0	6
Subtotal		12,928	11,790
Reclassified to long-term debt		(8,000)	(8,000)
Total short-term debt		$ 4,928	$ 3,790

[1] Weighted-average interest rates at December 31, 2015 and 2014, were 0.26 percent and 0.12 percent, respectively.